Politicians rarely give honest answers, especially during presidential election years. So rather than ask them what they think their party's chances are, you need to find creative ways to wring the truth out of them. My favorite torture implement is the veep test.

Put simply: How many likely running mates have publicly stated they're not interested? If the answer is "a lot," it's a sure bet they expect their guy to lose, regardless of what they say to the press.

On the Democratic side so far, Sen. Jim Webb (D-Va.) has said he's not interested in being vice president, but only after his disastrous intro of Sen. Barack Obama (D-Ill.) in Bristow, Virginia, this June. The scandal plagued—and likely baby daddy—John Edwards has also taken himself out of the running. That's about it, except for Ohio Gov. Ted Strickland's lame Gen. Sherman impression.

Sen. Evan Bayh (D-Ind.) has said he'd accept. New Mexico Governor Bill Richardson double-crossed his political patrons to have his own shot, earning him the nickname "Judas" from James Carville. The senior senator from Delaware is Biden his time and waiting for that phone call from his friend Barack. Even Obama's archrival Sen. Hillary Clinton (D-N.Y.) would like to help out—by muscling her way onto the ticket.

Republicans are reacting rather differently. Their most likely future standard bearer, Louisiana Gov. Bobby Jindal, has publicly taken his name out of consideration. So has Secretary of State Condoleezza Rice. And Connecticut Senator Joe Lieberman—who might as well be a Republican—has declared himself a non-candidate. Sen. John McCain's (R-Ariz.) economic advisor, the former snooping Hewlett-Packard CEO and political neophyte Carly Fiorina, stands a decent chance of landing the number two slot at this point—unless McCain is willing to make nice with hated rival Mitt Romney in exchange for an infusion of cash.

The veep test is only a measure of the current conventional wisdom, however, and does not necessarily herald good news for the Democrats or, for that matter, those Republicans currently telling McCain to take a hike. The great Whig statesman Daniel Webster famously refused the vice presidential nomination because he did not want to be buried before he was dead, a sentiment that cost him the presidency.

In 1968, Richard Nixon settled on Maryland Gov. Spiro Agnew after being waved off by several would-be veeps. But then the great Greek hope helped to secure key Southern states in a bruising, close election. Former President Gerald Ford effectively turned his rival Ronald Reagan down with talk of a "co-presidency" in 1980. Reagan went on to beat Jimmy Carter like a red-headed peanut farmer without him.

Especially in a tight election, the veep pick can be a much-needed wild card. But the pick doesn't always work out the way a presidential candidate might expect. In 1988, Texas Sen. Lloyd Bentsen turned out to be a great choice for the Democratic ticket. In fact, after he made horsemeat out of Dan Quayle in their debate, many people openly asked why he wasn't at the top of the ticket. It only made Massachusetts miracle worker Michael Dukakis look smaller by comparison.

Candidates pick running mates either to help nail down a state or to send a message. Lately, the win-a-state consideration has fallen out of favor, but maybe, in this message heavy year, retail politics will make a comeback. The parties are wisely holding conventions in Colorado and Minnesota, purple states that might go either way in the general election. All these states need is a good push. Perhaps each party's nominee will take a lesson from this in selecting their understudies.

Jeremy Lott is the author of The Warm Bucket Brigade: The Story of the American Vice Presidency.