From Australia to London to almost all points in between, if there are two things people know about Barack Obama, one of them is that he recently has changed his positions on abortion, gun control, capital punishment, FISA laws, the status of Jerusalem, faith-based federal programs, public financing of his campaign, welfare, NAFTA and free trade, the surge in Iraq, and his commitment to the Rev. Jeremiah Wright and his Trinity Church, among other public policies.

But it is said by his supporters -- and readily acknowledged by most public commentators -- that this is what candidates for president routinely do. If Republicans, they run to the right in the primary and run to the center in the general election. If Democrats, they run to the left in the primary and then to the center in the general. This is the policy version of the cynical Clinton defense: Everybody does it (although there is no evidence that any other president in history copulated a young White House intern). But we all know about the run to the center in presidential general elections.

Who can forget Ronald Reagan's 1980 campaign, when he came out for tax cuts, lower social spending and more military spending in the primary, only to back away from those policies in the general election when he famously said: "I got a little rhetorically over-excited during the primary. On closer examination, President Carter seems to have built up our defenses sufficiently. We will have to see about those tax cuts; we may need the revenues for more social spending."

Or what about the 1968 campaign, when Nixon ran on a law-and-order platform in the primary, condemning hippies, riots and the rising urban crime. Then, in the general election that fall, all the networks covered Nixon's extraordinary visit to death row at San Quentin prison, after which Dick Nixon explained, his eyes red from heartfelt tears (though some people say it was from squinting at the cross tabulations of his polls that showed he couldn't carry Pennsylvania without carrying liberal Montgomery County), that by talking with the men on death row, he realized that capital punishment wasn't the answer; more spending on early education programs was needed. He then claimed he had a secret plan to outspend Hubert Humphrey on urban renewal.

For one last example, consider George McGovern's 1972 campaign. He, of course, ran a powerful primary battle to end the war in Vietnam. On the floor of the Senate, he proclaimed: "Every senator in this chamber is partly responsible for sending 50,000 young Americans to an early grave. This chamber reeks of blood. It does not take any courage at all for a congressman or a senator or a president to wrap himself in the flag and say we are staying in Vietnam because it is not our blood that is being shed."

And then in September, he went to Vietnam to consult with the generals. Upon his return, he pivoted to the center. He announced: "Well, leaving may not be practical. The generals tell me just another 200,000 troops and we can win this thing. So what the heck; let's go for a victory, as all of the independent voters and most conservative blue-collar Democrats want. I may be progressive, but I'm practical. If I want to win this election, I've got to promise to win the war."

Of course, none of those things happened in past presidential elections. While some past presidential candidates may have emphasized more moderate parts of their agendas in the fall (although many, such as Reagan and McGovern, never even did that), I would appreciate Obama supporters (or others) bringing to my attention examples of straight-out reversals of one major position after another, such as Obama has executed recently.

I am not aware of anything remotely comparable to Sen. Obama's recent reversals of positions. To my knowledge, it is without moral precedent in modern American presidential elections. It is an act of political cynicism, compounded in its audacity by Sen. Obama's explicit claim to being above politics as usual.

This election season is getting interesting. Obama seems to have opened himself up to Dr. Samuel Johnson's famous admonition: "Be not too hasty to trust or admire the teachers of virtue; they discourse like angels, but they live like men."