WITH FRIENDS LIKE THESE . . . The 800-lb. president

The Lower 9th Ward of New Orleans is ground seldom trod by Republican presidential candidates. Yet presumptive party nominee John McCain picked his way through the rubble there last month before launching into a scorching criticism of the Bush administration. “Terrible and disgraceful” was his characterization of the administration’s response to Hurricane Katrina, which devastated the district in 2005.

The New Orleans stop was part of a sweep through hard-hit factory towns, African American strongholds and other spots where Democrats tend to get a warmer reception than the GOP, in what McCain’s campaign dubbed the “America’s Forgotten Places” tour. A more apt name might have been the “Ditch Bush” tour, because much of it was spent dumping on the administration that has forgotten those places. Nonetheless, McCain seldom mentions Bush by name unless pressed by reporters, even as he has staked out policy positions on many issues that are nearly identical to the incumbent’s.

If Bush is the monkey on McCain’s back, he’s also the 800-pound gorilla of Republican politics. As dearly as McCain would love to put distance between himself and a president whose approval ratings have gone lower than Richard M. Nixon’s at his nadir, he can’t possibly abandon the core GOP principles that won Bush two terms in office -- not least because McCain personally shares most of them and has been backing them in the Senate for decades. That puts him in a very tight spot.

“The change this country needs will not come from a third term of George W. Bush, and that’s exactly what John McCain is offering in this campaign,” said Democratic presidential front-runner Barack Obama in a recent speech. That has been a constant theme from both Obama and rival Hillary Rodham Clinton even while they’ve been savaging each other, meaning the cry will get even louder in the general election. It’s a smart strategy, given how badly Bush seems to have hurt Republicans in recent congressional races. On Tuesday, a conservative Democrat won a special election in what had been a staunchly GOP district in Mississippi -- the third defeat for a Republican in a special congressional race this year -- prompting senior party officials to warn candidates that if they want to win this fall, they had better do everything possible to cut the chain from the political anchor that is President Bush.

McCain has done quite a bit of sawing on that chain himself, and not just in New Orleans. On Monday, he delivered a speech on climate change -- at a wind-power company in the tree-hugging state of Oregon, no less -- that demonstrated his sharp break with the president on the environment. McCain has split with party orthodoxy by supporting mandatory limits on greenhouse gas emissions, and on Monday he got in a few deep digs at the current administration. “I will not permit eight long years to pass without serious action on serious challenges,” he said.

While that kind of language helps counter accusations that McCain is nothing but Bush’s smarter brother, it doesn’t come without peril. Polls show that Americans tend to think McCain’s positions on many issues are more liberal than they really are. His maverick stances on issues such as the environment and campaign finance reform only reinforce those impressions. That will undoubtedly help him among moderates this fall, but it turns off more hard-core conservatives. Some might question whether this matters -- after all, who else are they going to vote for, Obama? -- but it presents a danger that conservatives might simply stay home on election day.

To prevent that from happening, McCain is also tossing out slabs of red meat at every opportunity. Last week he gave an address excoriating liberal judges, a hot-button topic for social conservatives, and he likes to point out that he supports making Bush’s tax cuts permanent, a key priority for fiscal conservatives.

Of course, this is the same beef that Bush has been serving up for eight years. In fact, on the two issues of top concern to Americans, the economy and the Iraq war, it’s tough to discern any difference between McCain’s positions and Bush’s, which simply provides ammunition for the Democrats. McCain is boxed in -- damned if he does support Bush and damned if he doesn’t -- which is why we may soon hear him talking more about his war-hero past and his long experience in the Senate than about his policies.