From the stump, he lashes out at corrupt members of Congress and lobbyists. In TV ads, he blasts federal pork-barrel spending and government waste. He is the strongest champion on the Republican side for confronting global warming.
Generally speaking, McCain supports limited government and would like to give the states more autonomy.
An example is McCain's position on same-sex marriage. He believes it's a state matter and would back a federal constitutional amendment banning same-sex marriage only if the courts intervene at the state level.
McCain is in his fourth term in the Senate. Before that, he served two terms as an Arizona member of Congress. That followed a Navy career that included more than five years as a prisoner of war during Vietnam.
But one glaring hole in his resume is a lack of the sort of executive management experience one would get as a governor, a big city mayor or even the chief executive of a corporation.
McCain points out he does have some relevant experience beyond managing his Senate office and the Senate commerce and Indian Affairs committees that he has chaired. His Navy years included a stint as commanding officer of a squadron.
"I didn't manage it — I led it," McCain said at a Sept. 5 debate in Durham, N.H.
But critics look to McCain's presidential campaign, which underperformed, overspent and nearly went bankrupt this summer. An internal shake-up led to the resignations of Terry Nelson, his campaign manager; John Weaver, his longtime political strategist; and a massive staff downsizing.
"It's perfectly reasonable to judge a presidential candidate's management skills by how he or she runs the campaign," political scientist Larry Sabato says. "Obviously, McCain didn't do so well."
Others say McCain's long history on Capitol Hill should convince voters that he knows what he's doing.
Former spokesman Scott Celley compared McCain with President Eisenhower, who also entered politics from the military, albeit with higher rank and responsibility. Eisenhower was an Army general, McCain a Navy captain.
Anybody who rises through the military chain must display "some degree of management and organizational acumen," Celley says.