Earl Harold: Right to rule?

Harold Godwinson, popular and incredibly wealthy, was popularly elected king by the witan and was crowned on January 6th, 1066. 
With the ridiculous farce of the Norman "oath" of 1064 fresh in his mind, he knew that the only way to save the nation at that time was to take the available kingship himself.
He took the reins of a threatened and uncertain nation when the desperate times were 'right' for strong and proven leadership (then still under invasion threat from Tostig, duke William, the unsuspected Hardraada, and maybe others?)
The young Cerdic athling, Edgar, was too young (c.14yrs?) and militarily inexperienced and untested, and there is no record of him ever having revolted against this decision (even by the Normans)

Whatever Harold's eventual intentions for the crown really were (once England was safe maybe abdicating to become regent for Edgar or simply aiming to be chief adviser as his own father had been to Edward?), he knew that he was the only able, proven and experienced warrior in England capable of beating either of the formidable enemies imminently closing in-
  • a vengeful Tostig (ousted in 1065 and swearing revenge against him);
  • a formidable and hungry Duke William of Normandy;
  • a ruthless and feared Harald Hardrada of Norway
  • …or possibly even his own cousin Swein of Denmark?
Despite his half-Danish heritage and his relation to the Danish royal family (only via his mother Gytha, the sister of the Jarl Ulf, who married Canute's sister Estrith & fathered Swein of Denmark), Harold was considered quintessentially English in the 1060's and the strongest candidate for kingship should Edward die, despite his lack of royal blood in England.
He may well have descended back several generations to King Ethelred I (King Alfred the Great's elder brother and predecessor) and been 'royal' anyway?

After all, Edward the Elder had taken the kingdom of Mercia by virtue of his sister, Athelflaed via her husband Athelstan of Mercia(d.910), after her death in 918.

Harold was elected King to almost universal acclaim by the witan and the most powerful nobles in England, so if he willingly surrendered his throne (bestowed to him via the then all-important deathbed verbal succession promise by King Edward- in the presence of Breton/Norman Robert FitzWimarc) such weakness would seriously have compromised Harold's authority, power and prestige in the eyes of his followers who largely hated the Normans, and who expected a King to be dominant (Look at Edgar Atheling's example).

England had an enviable record of internal peace, unlike Normandy, guided for many latter years by Harold, and had avoided civil war by negotiation and compromise (ie. 1051/2 and 1065).
Harold had never previously attempted to seize power for himself or anyone else in England during the past 20yrs of loyal service as courtier and warrior in Edward's service, and he took charge of the wealthiest, most centralised and most effective fiscal, judicial and governmental state in W.Europe.
By the time the affable Harold was warrior-king of a v.wealthy England, this country had a highly evolved and complex taxation and administration system, which is why Duke William was keen to use Englishmen in the heart of his political and clerical regime for years. Even keeping Stigand in office- despite having invaded England- spilling Christian blood- to address the 'incorrupt' Saxon church!

Far from being the impulsive character often depicted in error, he was a capable and calculating diplomat/warrior- as he had proved by loyally and successfully serving King Edward. 
He patiently and successfully negotiating with the Welsh during the late 1050's and early 1060's on the king's behalf, plus dealing peacefully with the leaders of the mighty 1065 rebellion – (loyalty overshadowing his OWN brother Tostig's interests!)

In addition to also being well known to have authorised 'many just laws' in his short reign of 9mnths, Harold produced coinage from 44 mints. He produced as much coin in that short span as Harold I & Harthacnut did in several years!
This coinage(and predecessor Edward's) was a superior one to the shapeless, ill-struck coinages of King's Henry I, Stephen and Henry II, as well as the post-1066 coins that were rarely struck and were lacking in silver.

England was also powerful militarily, as Kings such as Alfred the Great (who saved Wessex, thus England later), his son Edward the Elder(whose 'Reconquest' from the vikings 910-18 was totally successful, and whose issue married into many continental royal families) and grandson Athelstan proved at the colossal battle of Brunanburh in 937 (he had been highly admired and praised on the continent, Ireland, around Britain and in Scandinavia).

Edmund Ironside(1016) defeated Canute and his Danish armies in five successive battles during 1016 and but for the battlefield betrayal of Earl Edric Stroena that year he would have ousted Canute from England.
Harold II(1066) himself proved that the Anglo-Saxons were a major military power, in 1063 against the Welsh and in the stunning victory over the mighty Hardrada at Stamford Bridge in 1066 in which the battle-hardened Norse Vikings were massacred. 

Snorri Sturlasson (in addition to praise from other Scandinavian poets) described just one of Harold’s Huscarls as;-
"better than two of Harald's [hardrada's] best men"...

Canute himself, not given to praising enemies (acc. To Henry of Huntingdon) considered the English soldiers to be;-
“ nec minori Dacos (not inferior to the Danes)”

William FitzOsbern
, William I’s steward, was said to described the English soldiery as;-
“Fortissimus (Most strong)”

William Poitiers even admitted that the English army were the;-
“ fiercest of men...always by nature ready to take up the sword"
had "easily defeated the King of the Norwegians"
had "resisted bravely" at Hastings
and the Norman/Bretons were "terrified by their ferocity"

Harold's 'oath' of 1064 (William's lynchpin of invasion) meant nothing to either him or the English elite- it had been extracted by the Normans under duress in the 'hospitality' of a provenly ruthless and cruel duke, stealthily disguised over "hidden relics" (Poitier's own words) beneath a cover and no doubt with more than a mere threat of coersion recognised in England as invalid therefore.
The post-1066 Normans couldn't agree when or where this alledged 'oath' was taken, even if it was outside or who was present! In any case, foreigners abroad had no say in the English succession- only the reigning king and the all-powerful witan could decide.
Having been handed to William via Edward in 1051, or snatched by a fleeing Robert of Jumieges in 1052, Harold's own younger brother Wulfnoth, and nephew Hakon, were still being held captive by the fearsome duke, maybe with the ever-present veiled threat of being plunged into one of many notoriously grim Norman gaols. Now Harold himself was in Norman 'hospitality'.
Maybe William would eventually have covertly tried to "do away with" Harold if he could find a convenient excuse and opportunity, as he had with several previous rivals such as King Edward the Confessor's own nephew, Walter of Mantes (who died along with his wife in one of William's dungeons), after William's invasion of Maine. Odd and callous thing to do if you're seriously considered for the English throne?
The duke didn't exactly prove himself tolerant of any neighbouring duchy (Maine; the disputed Vexin; Ponthieu; Boulogne, Brittany?) Canute also did away with many Saxon nobles and alledgedly assassinated his bitter rival and 'co-ruler' King Edmund Ironside in late 1016?

Robert of Jumieges, in 1052 being the recently ousted thus embittered anti-Godwinist fleeing to exile in Normandy, who had just lost all of his power, status and wealth in England in 1052 after the Godwin family returned triumphantly to England, thus every reason for being a catalyst for wanting change in England whilst taking refuge in Normandy, had strong motives for giving William(his master) a biased and probably innaccurate version of events and 'promised' words reputedly made from Edward's mouth, second-hand, according to Norman sources.

King Edward had, after all, also previously expediently promised his crown in the late 1040's to kings Magnus of Norway and Swein of Denmark- in both cases using this vague and shortlived pledge as a dangled carrot to pacify them and hope that they would not invade his realm, which they had both threatened to do- even building warfleets.

Northern England had been woefully weakened by the battle of Fulford Gate, 20th sept 1066, when the mighty Norse King Harald Hardrada and his huge invasion army landed and routed inexperienced, young brother-earls Edwin(Mercia) and Morcar(Northumbria).
Harold, as had Athelstan before him, rapidly gathered a southern and midland army to speed march 190miles north in just four days and surprised the victorious (above)Norwegians at Stamford Bridge(near York) on 25th Sept.
What followed was a brutal bloodbath which went on all day and was closely-fought. Harold eventually prevailed, killing over 90% of the Vikings- but with severely alarming losses of capable commanders and housecarls.
Whilst Harold's army recovered and reformed from this fantastic victory, news came that William had landed on the undefended southern beach over 250miles away!
Speed-marching south again to London (the King, Gyrth, Leowine, their commanders and housecarls would have been mounted, the army straggled behind on foot en route) Harold would have sent out messengers to call out another fyrd from the midlands, south and south-west to follow on and meet him at either London (for those still marching from the north) or at 'the hoare apple tree'(which to the Englishmen was a well-known spot near Senlac).

Spending just three weeks in London to make arrangements to deal with William and maybe gather intelligence- but fatally not wait for the bulk of the army he could have had in total available to him(as advised by his brother, Gyrth) he decided to dash to fight the Normans.
This has been seen as rash(not a characteristic of Harolds- he had proved an able statesman on King Edward's business many times before), but more likely he intended to;-

1. Hurry the c.80miles to pen the Normans into their stockade in the Hastings peninsula(maybe meet his army at Senlac and speed to Hastings to launch a night attack?) before their cavalry could break out into open English country and ravage as they were in his Wessex coast already.

2. Surprise the Normans as he successfully had done against the Norwegians 3wks before- before they became so entrenched and reinforced by sea that he could not oust them- they had not yet advanced inland and Harold may have supposed that they were not battle-ready.

Very nearly had Harold also won at the merciless bloodbath at Hastings- (even with a woefully weakened army after the brutal attrition of Fulford and Stamford Bridge only weeks before)- which even the Norman hagiographers grudgingly admit ("an unusually long battle" against the Anglo-Saxons who were "the fiercest of men…always ready to take up the sword"- Poitiers).

The military A/S system and martial abilities of the fighting men (housecarls, thegns and the general fyrd) were far from "obsolete"- as proved by the extreme campaigning and battles of 1066.
The exertions of that year would have strained any army, and the first two of the three massive pitched battles that year had taken a heavy toll of Harold's best men.
Even so, on October 14th 1066 the weary and depleted English fought a fresh and prepared 'modern' army to a standstill in a brutal all-day battle that was considered excessively violent even in that age. Whilst William was an equally great and ruthless general, but in command of a comparatively fresh, supplied and rested army… with cavalry and archers!

The Godwinson brothers had all been killed and many more surviving nobles despaired and sought to save themselves, seemingly after the king's death few had any heart to fight on.

Northern separatist brother-earls Edwin and Morcar - who had failed to show at Senlac for battle as far as we know- deserted the untested prince Edgar in London and fled northwards to avoid the approaching William (where was earl Waltheof?).
The atheling was too young(14?), apparently too weak a character to lead or inspire any remaining earls or troops- as the feisty but wounded Sheriff of London Ansgar did against William's men at the northern gate of London.
Too many Englishmen, especially the thegns, elite housecarls and commanders, had been lost that year to resist William after Hastings.
Men like Hereward and Edric the Wild were apparently abroad/exiled fighting as mercenaries on the continent at this point.

In English folklore and history, England under Harold (either as king or adviser) would very probably have gone on to become a very powerful nation without the direct continental influence, as it had already previously been admired by it's European, Irish and Welsh counterparts during the reigns of Alfred, Edward the Elder & the mighty 'emperor' whom Harold may well have gone on to become compared favourably to… king Athelstan "the Thunderbolt"…