John McCain has once again boarded the Straight Talk Express. You might recall that his bus trips and cozy conversations with the media brought victory in the New Hampshire primary in 2000, though not ultimately the Republican nomination for president that year. The bus symbolized that McCain was “a different kind of politician” and all the other cliches that have come to denote his public persona.

McCain’s back on the bus because his campaign for the GOP nomination has stumbled. Rudolph Guiliani leads in the polls, and McCain appears on the cusp of a death spiral. Politicians have long appealed to popular sentiment to attain power. The Straight Talk Express continues that tradition.

But how straight will McCain’s talk be? In 2000 in New Hampshire, he talked mostly about campaign finance restrictions. McCain’s current political problem comes in part from that “straight talk.” Republican primary voters don’t much support campaign finance restrictions. They understand correctly that the dominant purpose of such restrictions has long been to limit the speech and political activity of anyone who is not a liberal, a group that includes almost all of the Republican primary electorate.

So will McCain talk straight at his moment of greatest need? Will we once again hear of the corruption brought to politics by Big Money? Will he speak straight and forcefully against the Swift Boat ads in 2004?

This is a crucial moment for Senator McCain. He must talk incessantly about his support for restricting political speech. If he does not, Republican primary voters might conclude that McCain is just another ambitious, opportunistic politician who will say anything to gain power equal to desire.

And we know that is incorrect in his case, don’t we? After all, he talks straight.