Politics have, as Curly noted months ago, sunken to the level of “Ford Vs. Chevy.” Unfortunately, a lot of Chevy lovers failed to notice that all of the new models are being built in South Korea and the 8 cylinders are actually four cylinders when you look under the hood. The same can generally be said for the Ford owners too, but not quite as extreme.
A lot of traditional conservatives are anti war because, as Wotan points out, Iraq failed the test. They were anti-war before the war and see it as a mess today. These include Pat Buchanan (as noted) and:
George Will
U.S. forces in Iraq are insufficient for that mission; unless the civil war is quickly contained, no practicable U.S. deployment will suffice. U.S. forces worldwide cannot continue to cope with Iraq as it is, plus their other duties -- peacekeeping, deterrence, training -- without stresses that will manifest themselves in severe retention problems in the reserves and regular forces.
Since 9/11, Americans have been told that they are at war. They have not been told what sacrifices, material and emotional, they must make to sustain multiple regime changes and nation-building projects. Telling such truths is part of the job description of a war president.
http://www.townhall.com/columnists/georgewill/gw20040407.shtml
And read this article for a lot more. It’s from Antiwar.com, but then traditional conservatives tend to be anti-war when it’s not absolutely necessary. Many did not feel it was, or that it had any serious relationship to the War on terror, which was used as a means to achieve other ends. And, the neocons were once traditional liberals

It is a traditional conservative position to be against huge deficit spending…
It is a traditional conservative position to be against huge foreign aid, which has been almost a complete failure for many years now…
It is a traditional conservative position to be against the U.S. being the policeman of the world. That is exactly what we will be doing if we go to war in Iraq…
It is a traditional conservative position to be against world government, because conservatives believe that government is less wasteful and arrogant when it is small and closer to the people…
It is a traditional conservative position to be critical of, skeptical about, even opposed to the very wasteful, corrupt United Nations, yet the primary justification for this war, what we hear over and over again, is that Iraq has violated 16 U.N. resolutions…
It is a traditional conservative position to believe it is unfair to U.S. taxpayers and our military to put almost the entire burden of enforcing U.N. resolutions on the U.S., yet that is exactly what will happen in a war against Iraq…
Conservatives are generally not the types who participate in street demonstrations, especially ones led by people who say mean-spirited things about our President. But I do sincerely believe the true conservative position, the traditional conservative position is against this war. http://www.antiwar.com/orig/duncan1.html
Here’s another good link on the same:
Most respondents assumed that because I and other academics have criticized Bush policies, we must all be left-wing radicals who hate America (or in other words, "Democrats"). A typical letter read: "Strength is all the terrorists understand, not anti-American mutterings by a few so-called intellectuals. The Democrats have lost the House, the Senate, soon the White House, and soon the Supreme Court. Wake up, you're out of touch with the country."
But those who assume that the administration's critics are all Democrats or "clueless lefties" are wrong. I'm a registered Republican who twice voted for Bush's father.
http://www.indystar.com/articles/0/182591-1310-021.html
Or this (pretty detailed actually):
"Historically, conservatism in the United States has meant support for small government, balanced budgets, fiscal prudence and great skepticism about overseas adventures," notes Clyde Prestowitz, a former Reagan Administration official who back in the 1960s was among the young Republicans supporting Arizona Senator Barry Goldwater, a conservative standard-bearer. "What I see now is an Administration that's not for any of these things."
In the April 2004 issue of The American Spectator, Halper and Clarke argue that, contrary to the gunslinging figure neoconservatives invoke, Reagan was a conservative internationalist who structured his foreign policy around containment and diplomacy, an approach many neoconservatives dismissed as shreckless at the time. (In 1981, for example, Reagan resisted pleas from hard-liners to place an economic embargo on Poland after Warsaw cracked down on the Solidarity movement, a decision characterized by the neoconservative Norman Podhoretz as "following a strategy of helping the Soviet Union stabilize its empire.")
http://www.thenation.com/doc.mhtml%3Fi=20040531&s=press
Of course there were the Generals, like Zinni:
Anthony C. Zinni's opposition to U.S. policy on Iraq began on the monsoon-ridden afternoon of Nov. 3, 1970. He was lying on a Vietnamese mountainside west of Da Nang, three rounds from an AK-47 assault rifle in his side and back. He could feel his lifeblood seeping into the ground as he slipped in and out of consciousness.
He had plenty of time to think in the following months while recuperating in a military hospital in Hawaii. Among other things, he promised himself that, "If I'm ever in a position to say what I think is right, I will. . . . I don't care what happens to my career."
That time has arrived.
Over the past year, the retired Marine Corps general has become one of the most prominent opponents of Bush administration policy on Iraq, which he now fears is drifting toward disaster.
http://www.washingtonpost.com/ac2/wp-dyn?pagename=article&contentId=A22922-2003Dec22¬Found=true
Charon