John Kerry fancies himself a very disciplined politician who never tips his hand. But in his hunt for a running mate, the presumed Democratic presidential nominee may have revealed more about himself than he had in mind.

Kerry is now interviewing potential running mates in his own party. But regardless of how he tries to dress it up, today's candidates are backups. The original object of Kerry's affection -- the person he personally courted for the second spot on the Democratic ticket -- was Arizona Republican Sen. John McCain. That McCain wasn't interested in the job is now old news. That Kerry had actually turned to a conservative Republican is an insight into the man and how he might govern if elected.

What made Kerry do it?

Yes, the two senators are good friends. McCain even stuck up for Kerry when the Bush campaign tried to question the Democratic nominee's patriotism. And, yes, there are polls that suggested a bipartisan ticket of these two war heroes would be popular, especially among independent voters. What's more, McCain is also highly regarded for his independence, courage, integrity and willingness to take on the Bush administration -- qualities that make him the kind of politician any Democratic presidential nominee would want on his or her side. But a heartbeat away from the presidency?

Apart from campaign finance reform, on which McCain is a standout, his record on a number of critical social and civil rights issues, including judicial nominations, places him firmly in the Republican Party's right-wing camp. It was McCain, for example, who lined up with fellow Republicans in supporting President Bush's ideologically far-out nominees to the federal appeals courts. Moreover, McCain has:

* Voted against a bill declaring the third Monday in January a federal holiday honoring Dr. Martin Luther King Jr.

* Voted to cut off federal assistance to public schools that prohibit prayer in school.

* Voted to strike provisions of the Racial Justice Act that would prohibit the death sentence in state and federal cases if a defendant could prove with statistical or other evidence that the race of the victim played a role in sentencing.

* Voted against a 1996 bill to prohibit job discrimination based on sexual orientation.

* Voted against measures to increase the minimum wage, against a woman's right to choose, and with Bush 91 percent of the time last year.

What's more, in wooing McCain, Kerry sought to put on the Democratic ticket a GOP senator who voted for articles of impeachment that would have sent President Bill Clinton packing from the White House.

So why did Kerry pursue McCain?

The Massachusetts senator obviously feels a need to compensate for his liberal voting record. What better way to do that, I suppose, than to tap a conservative budget hawk such as McCain who also appeals to mainstream, suburban independent and Republican voters?

So what if picking McCain would have meant turning to the right and away from moderate Democratic candidates? The Kerry camp believes Democrats are willing to do -- or tolerate -- anything to break George Bush's hold on the White House. Kerry insiders are counting on differences with the Bush administration on jobs, health care and tax cuts to keep Democratic voters in Kerry's camp.

Besides, goes the thinking, so what if grass-roots Democrats are disenchanted with Kerry? Where do they turn? To the party of Bush, Dick Cheney, John Ashcroft and Donald Rumsfeld?

That, by the way, was the thinking of Maryland lieutenant governor and Democratic gubernatorial candidate Kathleen Kennedy Townsend two years ago when she tapped a former Republican, Adm. Charles Larson, to be her running mate. She, too, thought a prominent ex-military officer and longtime Republican on her ticket would appeal to conservative voters who weren't likely to look her way. It turned out, however, that Larson, a former Naval Academy classmate of McCain and a supporter of McCain's GOP presidential bid in 2000, was of little help to Townsend at the polls.

Her party's most loyal constituency, African Americans, hurt by her snub of better Democratic candidates and angered by her taking them for granted, failed to turn out on Election Day as she needed.

A McCain on the Democratic ticket would have put Kerry in a similar strained position with his Democratic base. A Kerry-McCain pairing might have been a dream team for pundits, editorial writers and the political elites. But John McCain would have been as hard a sell in urban America as Charles Larson was in Baltimore and the Washington suburbs. McCain did Kerry a favor by saying no.

One more thing. Despite what Kerry may have been told by his handlers and fundraisers, his candidacy is not a sure thing in communities where concerns for justice, civil rights and economic empowerment are live issues. Townsend found that out for herself. Kerry needs to keep that in mind. His dalliance with McCain didn't win him any points in precincts that can make or break him in November.

But at this moment, with campaign funds pouring in, Democratic politicians pledging their unwavering support, and John Kerry's deep, abiding faith in his own political brilliance and that of the inner circle around him, why should he worry? Wait till he gets to the White House.

He probably still thinks John McCain was a good idea.

kingc@washpost.com