McCain released a new ad that says one of Bush's commercials "twists the truth like Clinton." Bush responded with a commercial taking aim at McCain's core message -- campaign finance reform -- and saying the senator "solicits money from lobbyists with interests before his committee and pressures agencies on behalf of contributors."

The hot words flew as Bush got a much-needed lift over McCain's insurgent candidacy with an easy victory in Delaware's Republican primary. McCain did not campaign in Delaware, bypassing it to campaign in South Carolina and Michigan.

The Texas governor said he had a record of reform and McCain was not the political maverick he claimed, repeatedly referring to the senator as "the chairman" and saying that as head of the Senate's Commerce Committee and as a campaigner he "tends to say one thing and do another."

The latest example, Bush said, was McCain's statement a day earlier that he had always opposed public funding of elections. The Bush campaign offered a list of five McCain votes from 1990 to 1993 in favor of a bill that proposed partial public funding of Senate campaigns.

"Senator McCain voted not once, not twice, but five times to support publicly funded congressional campaigns," Bush told reporters after speaking to a cheering student crowd at North Greenville College.

McCain, campaigning in South Carolina, said he couldn't recall whether he had ever voted for public funding of federal campaigns, but that he was philosophically opposed to the idea "because of my view that my tax dollars should not be used to subsidize the campaigns of another candidate."

His spokesman, Howard Opinsky, said: "This is the same old Washington Clintonian politics that voters have become so cynical about, trying to twist John McCain's 17-year record of reform and consistent opposition to public financing to Governor Bush's advantage."

Opinsky said all of the votes were against cloture motions -- that is, voting to continue debate -- to keep opponents from stifling campaign finance reform.

In Columbia, meanwhile, McCain announced a plan to fight crime and drugs, but the event was all but buried by questions from reporters about his disputes with Bush.

McCain, the former Vietnam prisoner of war, said he was offended by a Bush ally who questioned his commitment to veterans -- a comment McCain said was "beyond the pale" -- as well as by aggressive new Bush ads. He noted that he and Bush had shaken hands just weeks ago and agreed not to air negative ads against each other.

"I believe it is not trustworthy when someone shakes your hand and says they're not going to run a negative ad, and then runs a negative ad," he said aboard his bus.

"We've already got somebody in the Oval Office who is not trustworthy," he said. He went even further in a new TV ad that says one of Bush's ads "twists the truth like Clinton."

The charges and countercharges come as Bush and McCain court veterans, who along with active-duty military make up a substantial portion of the GOP electorate here. The state primary is Feb. 19, and Bush views the state as his political "firewall" to stop McCain's momentum after the New Hampshire primary.

EDITOR'S NOTE -- AP writer Scott Lindlaw contributed to this report.