The Democrats are trying hard to sell the idea that a McCain presidency would amount to a third term for President Bush. That's tactically advisable, given the president's extraordinary unpopularity.

Unfortunately for them, it is Barack Obama, not John McCain, who promises to repeat the worst mistakes of the Bush administration.

Democrats are quick to condemn President Bush's Iraq war policy as "faith-based" and excessively ideological.

Knowing that people prefer freedom to slavery, Bush had faith that democracy would quickly emerge in Baghdad once Saddam Hussein was overthrown. He clung to that faith long past the point when impartial observers had concluded that the administration's hopes for the rapid establishment of a flourishing democracy in Iraq had proven false.

McCain supported the Iraq war but was an early critic of the Bush-Rumsfeld plan for fighting it. He was among the first to call for more troops and the adoption of a genuine counter-insurgency strategy.

Belatedly, under the compulsion of events, Bush directed Gen. David Petraeus to do exactly that. In consequence, our Iraqi allies and our forces are enjoying increased security. Political progress is finally coming to Iraq.

Obama opposed the invasion of Iraq from the start, and he must be given credit for having appreciated the terrible costs the war would impose. But Obama's position about what to do now is nothing but the mirror image of Bush's early war policy.

Knowing that he would not have invaded Iraq, Obama clings to the faith that our forces must be withdrawn as soon as possible. He holds firm to that faith long past the point when impartial observers have concluded that Sen. Harry Reid's declaration of failure in Iraq has been proved false.

Democrats also like to bash Bush for his unilateralist foreign policies and his scorn for our treaty obligations.

But it is Obama, not McCain, who today speaks the language of unilateralism. It is Obama, not McCain, who threatens to abrogate our obligations under NAFTA in the hopes that such bluster will induce Canada and Mexico to renegotiate that treaty. It is Obama, not McCain, who threatens a unilateral military attack in the territory of our (nuclear-armed) ally, Pakistan, in the event that the Pakistanis do not act on "actionable" intelligence indicating the presence of al-Qaida terrorists in their country.

Democrats also scorn Bush for what they regard as his duplicity, but most of my Democratic friends have assured me that Obama doesn't mean the tough talk on trade and Pakistani terrorists. Apparently, he just needs to say those things to appease bitter and insecure downscale white voters.

At home, Democrats charge that Bush has managed our national finances so recklessly that, from now on, drunken sailors will have to say at the end of their sprees that they had spent their money like sober Republicans. Sadly, there is much truth to this charge.

But the question now is: Will McCain or Obama manage the public finances more effectively starting in 2009?

It does not augur well that McCain says that he would reauthorize the Bush tax cuts while Obama says that he would not. But those statements don't matter because those cuts are set to expire anyway, and there is no chance that the Democratic Congress we are sure to elect in 2008 will vote to reauthorize them.

If McCain is president, he may want to reauthorize the Bush tax cuts, but he will not get the chance. The Democrats in Congress will want to increase expenditures, but McCain will have every incentive to block them.

Like McCain, a President Obama would preside over the automatic tax increase that will kick in when the Bush tax cuts expire, but he will have trouble resisting his Democratic colleagues' pent-up demands to increase spending and keeps proposing new spending ideas himself.

Bush couldn't restrain a Republican Congress from spending recklessly, but he didn't try very hard. President Carter did try to restrain his Demo-cratic Congress, and what thanks did he get?

A primary challenge from Ted Kennedy.

Finally, the Democrats object to Bush's fierce partisanship. But unlike McCain, who has broken with his Republican colleagues on such high-profile issues as immigration, global warming and the treatment of terror suspects, Barack Obama cannot point to a single major issue on which he has defied the wishes of his party's ideologues.

Luckily for Obama, even McCain is not maverick enough to start calling him "Barack W. O'Bush." But maybe he should.

Joseph R. Reisert is associate professor of American Constitutional Law and chairman of the Department of Government at Colby College in Waterville.