"1: It expends resources of key air power that is currently used in Iraq and Afghanistan."
no, we have air and sea power that can bombard that is already within range to do so.
"2: Replacing lost missiles, lost aircraft, and hazard pay increases for wartime soldiers creates a short term financial burden on the US government."
in a country with the economy of the US, that financial burden for a bombardment is minimal. the financial burden to North Korea to being a victim of the bardment would be much more significant.
"3: An anti-war candidate lobbying for a preemptive war against North Korea would be extremely damaging politically."
not a preemptive war, a bombardment. no more damaging then Clinton bombing Iraq; which wasnt damaging at all.
"4: Best case scenario, there would be disruption of trade with a key trade partner, South Korea. Worst case scenario, South Korea could be devastated in the conflict."
best case scenario, and most likely scenario, no disruption with South Korea. If North Korea did invade South Korea or attack them, because of an american bombardment, the US would have an international coalition against North Korea.
"5: Didn't Vietnam show you that air power is useless without ground support? Unless you can take control of the weakened territory, structures can be rebuilt, borders can be fortified again, and supply lines can be redrawn."
in a war, absolutely its useless. but financially, its devastating to the country being bombed. you think that the costs of the bombardment id devastating for the US, with its huge economy, and not being the target of the bombardment, with North Korea's tiny economy, its 100 times worse for them. gonna have a hard time affording nuclear research when they're spending all their resources repairing the damage the bombardment has done.
"6: You can't secretly mobilize large-scale forces. The US wouldn't be able to hide its military movements from the Press, let alone North Korea. It's just impossible for us to say, "Oh, by the way, remember that aircraft carrier we said yesterday was parked in the Persian Gulf? April fools! It's actually just short of North Korea! Just got there, and now we're gonna blow up the place! GG, Kim!"
the US already has a carrier group in the region.... so you fail once again.
naval bomardment would be better imo. i bet North Korea has decent anti-aircraft, and naval bombardment would elimninate chance of POW's, which North Korea could use as bargaining chips.