How realistic are the fears of hawkish presidents?

Last night at dinner with a couple of friends who are civil liberties lawyers, I asked why they thought Obama had changed his tune on surveillance; from campaigning for limited, closely overseen, transparent surveillance regimes to establishing a secretive, overarching, totalizing surveillance system that necessitates prosecuting more whistleblowers than all the other presidents in American history, combined.

They suggested that Obama might have taken office and been immediately assailed by surveillance-happy spooks who assured him that the world was full of existential terrors and that if he did anything to get in their way of Total Information Awareness, he would be drummed out of office in ignominy as the president who let America get attacked. Like LBJ, one friend said — never wanted to ramp up the Vietnam war, but didn't want to turn his administration into the administration that lost a war.

Which got me to thinking: has there ever been a US president who cost his party the next election (or lost office) by being insufficiently hawkish about some war? By having an attack on his watch? GWB would probably have been an embarrassing one-termer but for Osama bin Laden (whom GWB never caught, incidentally, and this never seemed to be taken for weakness in his campaigns and in the campaigns of his would-be successors).

I'm no scholar of US history, but some of you are. Is it realistic to think that a president who isn't a big enough hawk will cost his party the next election, or be remembered in history for leaving America vulnerable to the Kaiser/Osama/the Spanish Armada/General Santa Ana/whatever?