Here's the thing tho...Hawaii was important; back when ships ran on sail and/or coal, before planes could fly non stop round the world, before labor laws and unions and the constitution put an end to profitable agriculture.
Nowadays, we have tourism and Inouye, pretty much the only reasons why anyone has stuck around, including the military.
Hawaii has no resources, therefore it will not be invaded, ever.
Hawaii produces nothing worthwhile to justify invasion.
Hawaii is not targeted by any countries ICBMs.
Even terrorist could care less about Hawaii.
On topic, the best way I see to stop/resist an invasion would be, to not write letters, but to form community militias now.
You have got to be kidding? You obviously have no knowlage of military history, strategic tactics, or have a realistic idea of what modern military equipment is capable of.
Warships need more than just fuel! food, ordinance, spare parts, etc. A ship at war grinds through these things faster than fuel.. even back in wwII fighting ships had to had to resupply ordinance and consumable foodstuffs before they ran out of bunkerage. Just because a nuclear powered warship can run for years on its reactor, does not mean it doesnt need resupply. And while a civilian airliner can fly a great distance, even the longest ranged military aircraft are limited by how much arms they can carry for the amount of fuel they can hold. Only the Russians, the US, and Brittan ever developed large military jet aircraft with intercontinental range and enough payload to make it worth sending out into enemy territory. Even with air to air refueling, nither china or north korea have aircraft that can reach hawaii with a useful ordinance load. So we really dont need to worry much about getting bombed. But china could glass us with an ICBM if they wanted to...
However... if the islands were taken intact...
The strategic value of the hawaiian islands cannot be understated naval assets alone would justify thier taking or neutralization. (lets not forget several airports with sufficent length runways to stage large, ordinance laden strike aircraft out of...
There is pearl, barking sands, and several other high value targets that were deffinitely on Ivan's menu back during the great unpleasantness. Not primary targets, but after they glassed washington, NORAD, and the midwest missile fields and SAC bases (including guam) next on the list would have been the deepwater ports on the us east and west coasts, pearl harbor, the cobra dane radar facility in alaska, and... barking sands. So yeah, if we had a full on nuclear war with russia, we'd have been skullfucked. 23 or 4 russian SS23s would have done the job for the whole state, four 500kt MIRV warheads each, a mere quarter of the payload of a single DELTA IV sub. The soviets had 18 of them by the way...
Chances are pearl is on china's menu, if things got stupid. maybe not a primary target, but deffinitely on the map.
One thing we dont really need to worry about is a full scale invasion... only a few countries still have the amphibious assault assets to land enough grunt to take a large target. All of them are allied with the us. (I would count russia as a limited ally at this point) China's amphibious assets are limited, IF they could get thier navy from mainland china to hawaii intact (not happening... our fast attack subs and aircraft carrrier battle groups would make mincemeat of the chinese navy) they could ( maybe) invade one island with a brigade sized force.. we can land entire fighting DIVISIONS... Hitting oahu with a small amphbious force backed up with airborne infantry would be a clever way to destroy your elite units for little gain before they were pushed back into the sea.
As for north korea, thier navy and airforces are a joke... yeah... they have a big army... of mistreated conscripts. And at this point thier missile technology is equal to where the soviets and we were... in like the late 1950s. The north koreans are not dangerous to us at this point. Only thing imworry about with them is if they get suicidal/stupid and loft one at japan or south korea... we will have no choice but to respond in some fashion, and we dont want to send our boys back to korea to fight a ground war... not again.