WASHINGTON  - Hillary Clinton's virulent attacks on Barack Obama during their primary epic returned to haunt her Thursday as Republican White House hopeful John McCain stepped up an anti-Obama advertising blitz. A new Internet ad from the McCain campaign, featuring the former first lady as its unwitting star, threatened to reopen Democratic wounds at a delicate time for the party ahead of its presidential convention later this month. "John McCain is a maverick - just ask Democrats," a caption reads in the broadcast, which came a day after Obama dismissed McCain's "maverick" credentials by casting him as a tired retread of President George W Bush. The Republican's spot features old footage of prominent Obama supporters, including senators John Kerry and Joseph Biden, praising McCain as an honourable politician who is unafraid to reach across party lines. It even includes a snippet from Obama himself, in January 2007, lauding a Senate bill co-sponsored by McCain on greenhouse gas emissions. But the real sting comes with the final guest speaker - Hillary, shown making a biting remark about Obama at the bitter height of their primary battle for the Democratic nomination in March this year. "I know Senator McCain has a lifetime of experience he will bring to the White House. And Senator Obama has a speech he gave in 2002," she says in the ad, referring to Obama's stand against the Iraq war. There was no immediate response from Press aides to Obama, Hillary and other Democrats featured in the ad. Hillary faced angry criticism during the primaries that she had crossed a line by explicitly praising McCain to the detriment of Obama, and was warned that those attacks would return to stalk the likely Democratic nominee. Another now-infamous attack from Clinton, in a television spot, questioned whether Obama had the leadership mettle to cope with a foreign policy crisis in the dead of night. However, US Secretary of State Condoleezza Rice said in an interview with Politico and Yahoo News released Thursday that the nation would be "fine" under an Obama presidency. But Republican Rice, discounting any vice-presidential ambitions of her own, also said McCain was "a fine patriot and he would be a great president." Writing in the Huffington Post just after Hillary Clinton's "lifetime of experience" remark, former Democratic presidential contender Gary Hart said there were unwritten rules in politics. "One of those rules is this: Do not provide ammunition to the Opposition party that can be used to destroy your party's nominee. This is a hyper-truth where the presidential contest is concerned," he wrote. McCain spokesman Tucker Bounds confirmed it was the campaign's first use of a Hillary attack line from the primaries, and promised more to come. "We don't go into our media strategy but it's not unlikely that she will figure in further ads," he told AFP. The ad was the latest shot of an advertising barrage by McCain that has portrayed Obama as a vacuous celebrity whose economic plans would endanger middle-class prosperity. Obama has fired back with ads recapping the Republican's boasts that he has cast Senate votes in lock-step with Bush policies, and his belief that hard-pressed Americans are better off today than eight years ago.