On trade, for example, he recently told Fortune magazine that he would never withdraw from NAFTA, calling some of his sharpest anti-trade rhetoric "overheated." "I've always been a proponent of free trade," he said.
But he was fiercely critical of trade deals in his primary fight with Hillary Clinton, especially before union audiences, and he threatened to abrogate the pact with Canada and Mexico if they did not agree to changes in its terms.
In the aftermath of the Supreme Court's ruling that struck down the District of Columbia's gun ban, he issued a confusing statement that said he has always believed in the constitutional "right of individuals to bear arms." But he supported gun control as a state senator in Illinois, and a staffer told the Chicago Tribune last year that "Obama believes the D.C. handgun law (banning private ownership) is constitutional."
On FISA, he said earlier this year, "There is no reason why telephone companies should be given blanket immunity to cover violations of the rights of the American people."
But as the administration-backed FISA bill was cleared for debate last week in the Senate, he shifted sharply to the right, saying, "It is not all that I would want. But given the legitimate threats we face, providing effective intelligence-collection tools with appropriate safeguards is too important to delay."
Throughout his campaign, he has railed against "tax breaks for big corporations" and attacked John McCain's call for cutting corporate tax rates. But in a recent interview with the Wall Street Journal, he said he would consider cutting their taxes as part of a tax-simplification plan.
Even on the core issue of Iraq withdrawal, he seemed to be wiggling away from a full pullout. "Three or four of his Iraq advisers are hinting of greater flexibility," said Democratic defense analyst Michael O'Hanlon at the Brookings Institution. "That indicates the potential for some change in his previous position or at least some flexibility."
In a recent conversation with Iraq's foreign minister, Hoshyar Zebari, Obama reassured him that "he will not take any drastic decisions or reckless actions" and would consult "very closely with the Iraqi government and the military commanders in the field" before any troop withdrawals, Zebari told the Wall Street Journal.
All of these and other changes in his campaign positions were "signs of increasing maturity and growth" in the young senator, former Democratic National Committee chairman Steve Grossman told me.
Or are they, as the McCain campaign charges, Obama's willingness "to say or do anything it takes" to win the presidency?