As sure as IP and Tacitus tell it, a disaffected base spells doom for an incumbent president. President Bush has certainly disappointed a number of rightist constituents - primarily orthodox fiscal conservatives - and from the observations of journalists, bloggers and average voters, a debate may be swelling within the Republican Party as to how entitled their executive is to retain his office.

But how big will that debate be - and how much significance might it have on this November's election? With New Hampshire having dominated political headlines for nearly a week, now practically drowning all domestic news, I found myself reading Fox News' nicely organized list of New Hampshire primaries for both parties. In it I found a pattern: incumbent presidents who were challenged by another candidate within their party insofar as to lose more than a third of the vote lost in the subsequent general election. General election results for incumbents capturing at least two-thirds of voters' support varied, dependent upon the relative success or collapse of their opponents' campaigns.

While I'm certainly not the first to observe it, I haven't yet read of its application to the 2004 presidential election. That's surprising, since this phenomenon has held true for every single election since 1956:

Republican Primary, 1956, Dwight D. Eisenhower: 98.9% of the New Hampshire vote. Landslide victory against Adlai Stevenson, 457-73.

Democratic Primary, 1964, Lyndon B. Johnson: 95.3% of the New Hampshire vote. Landslide victory against Barry Goldwater, 486-52.

Republican Primary, 1972, Richard M. Nixon: 67.6% of the New Hampshire vote. Landslide victory against George McGovern, 520-17.

Republican Primary, 1976, Gerald R. Ford: 49.4% of the New Hampshire vote. Defeated by James Carter, 297-240.

Democratic Primary, 1980, James Carter: 47.1% of the New Hampshire vote. Handily defeated by Ronald Reagan, 489-49.

Republican Primary, 1984, Ronald Reagan: 86.1% of the New Hampshire vote. Landslide victory against Walter Mondale, 525-13.

Republican Primary, 1992 George H.W. Bush: 53.2% of the New Hampshire vote. Defeated by William J. Clinton, 370-168.

Democratic Primary, 1996, William J. Clinton: 84% of the New Hampshire vote. unopposed. Solid victory against Robert Dole, 379-159.

What did all the losing incumbents have in common? The obvious: a disaffected base willing to risk substituting their party's current occupant of the White House. This in turn led the base to sit on their hands or vote for the other candidate - otherwise helping their incumbent towards retirement. Ford's downfall was his association with Nixon and Watergate; Carter's economic, military and diplomatic failures foundered party confidence; Bush's flagrant violation of his central election platform plunged a wedge in between him and voters.

What about the winners? Although Richard Nixon's two-thirds win was the oddity - all other winning incumbents took five-sixths or more - a clear numerical median distinction lay between presidential incumbents who did not please everyone in their party and those who truly angered their party. What's more is that the ever-threatened "stay-at-home protest" was superfluous to these events. If a president found himself in deep water with his brethren, it was apparent in New Hampshire - every time. No incumbent was fooled by a breezy, unopposed contest.

What does this mean for Bush? If New Hampshire's primary remains a bellwether: Either mutiny develops from nothing immediately, in the form of [a serious] opponent or a protest vote, or the signs of Republicans unhappy with one or another aspect of President Bush's performance - through polls or anecdotes - won't show up in the ballot box.

THEY VOTED FOR HIM: George W. Bush joins the ranks of presidential incumbents achieving wide party support in the New Hampshire primary.

UPDATE: The official tally has been adjusted to 80%, so Bush's performance is numerically inferior to Reagan and Clinton. (And I've removed a post questioning Deroy Murdock's use of the figure.) It's odd to see Mickey Kaus boasting, though, seeing as how immediately after the primary, he didn't even check to see what 87% meant in historical terms. 79% certainly forecloses on GOP bragging rights, but it doesn't prove much more beyond that. The absence of both a serious party challenger and significant voter diversion to him has yet to be explained away. If pundits want to ask a question, they should ask why Bush isn't doing as poorly in the ballot box as some seem to think he would have. Or they can look at Ford, Carter and H.W. Bush to see incumbents who were truly in trouble.

The theory still applies.