McCain's challenge: Break from Bush, but not GOP

Today, John McCain gets what one political scientist calls a Hubert Humphrey moment.

Forty years ago, Humphrey's ties to an unpopular president from his own party bogged down his presidential campaign. Late in that 1968 campaign, Humphrey removed his vice presidential seal from his podium, a symbolic sign of his break from President Lyndon Johnson and the Vietnam War.

It started turning the tide his way – many said he'd have won if the election had been a week later – but it was too late.

Tonight, McCain gets his chance to show the country how he'd break with an unpopular president from his party, George Bush.

It's a tricky opportunity. Bush remains popular with many Republicans, but McCain also needs to appeal to independents who don't like Bush and who could be crucial in a close election. The Republican presidential candidate also needs to reach beyond them to the vast majority who think that the country is on the wrong track.

The key: reasserting his credentials as a maverick willing to buck his party while also framing a fall campaign that challenges Barack Obama, the Democratic presidential nominee, over who could really change Washington.

“It's his Humphrey moment,” said Dennis Goldford, a political science professor at Drake University in Iowa.

“McCain has to make the case that while he's a Republican, he's different. He's got to show what a McCain presidency would do differently from both the Democrats and the Bush administration.”

Some of the points McCain is likely to make:

He broke with the Bush administration over Iraq, criticizing the strategy of Bush at considerable political peril and pushed for the surge of additional troops that, along with other factors, has reduced violence there.

He's been a vocal critic of pork-barrel spending – even by his own party.

He came out first in support of offshore oil drilling to ease U.S. reliance on foreign oil, prodding the White House to change its position.

He's also likely to stress that he knows how to change Washington from the inside, a response to a line in Obama's acceptance speech last week that, “Change doesn't come from Washington, it comes to Washington.”

Watch for McCain to tell viewers that he has a record of building bipartisan coalitions to reform the way politics or government works, such as the McCain-Feingold law regulating the flow of money to political campaigns and attempting to regulate what interest groups can say on television before an election.