WRAPUP 3-Obama, Clinton trade charges in speech flap

(Adds Clinton commennt, paragraphs 3-4)

By John Whitesides, Political Correspondent

NILES, Ohio, Feb 18 (Reuters) - Democrats Barack Obama and Hillary Clinton traded charges on Monday over Obama's uncredited use of a friend's lines in a speech, one day before the presidential contenders meet in a critical showdown in Wisconsin.

Pointing toward Tuesday's primary, the two camps battled over a recent Obama speech using words from Massachusetts Gov. Deval Patrick -- a friend and political ally of Obama. Obama said he should have credited Patrick but dismissed the controversy as no big deal.

Hillary Clinton, speaking to reporters in Madison, Wisconsin, aboard her plane, was asked about the issue.

"If your whole candidacy is about words, they should be your own words. That's what I think," she said.

Clinton spokesman Howard Wolfson said the use of the lines called into question Obama's rhetoric -- one of the Illinois senator's biggest selling points.

"Senator Obama is running on the strength of his rhetoric and the strength of his promises and, as we have seen in the last couple of days, he's breaking his promises and his rhetoric isn't his own," Wolfson said.

The exchanges came before Tuesday's votes in Wisconsin and Hawaii, which will allocate a combined 94 delegates to the August convention that selects the Democratic presidential nominee in November's election.

Polls show a tight race in Wisconsin as Obama tries to extend his string of eight straight victories in Democratic nominating contests, which have given him a lead in the race for pledged convention delegates.

Obama, who was born in Hawaii, is favored to win in that state.

Republican front-runner John McCain earned the endorsement of former U.S. President George H.W. Bush, the father of the current president, at a Houston meeting.

The elder Bush said he was annoyed by conservative attacks on the party's almost certain nominee and called their criticism "grossly unfair."

"You know, if you've been around the track you hear these criticisms and I think they are grossly unfair. He's got a ... sound conservative record but he's not above reaching out to the other side," Bush said at a joint news conference with the Arizona senator.

Some conservatives distrust McCain for his moderate views on illegal immigration and campaign finance reform and for voting against President George W. Bush's tax cuts in 2001 and 2003. McCain, hoping to mend fences with conservatives, now wants to make the cuts permanent.

Later, aboard his campaign plane, McCain said he would be glad to have the current president campaign on his behalf "under any circumstance." Bush has suffered from low approval ratings, particularly among independent voters whom McCain would hope to attract in the November election.