Former Republican presidential hopeful Mitt Romney endorsed erstwhile rival John McCain on Thursday and urged Republicans to unite behind him in a gesture that could help McCain with disgruntled conservatives.

In the Democratic race, Senator Hillary Clinton scored a much-needed victory in New Mexico and accused surging opponent Barack Obama of lacking substance and experience as she fought for political traction in Ohio after a string of losses.

After a rough campaign battle between them to be the party's nominee in November's election, Romney offered conciliatory words to McCain a week after dropping out of the
race, calling him an American hero.

'Even when the contest was close and our disagreements were debated, the caliber of the man was apparent,' Romney said with McCain at his side. 'This is a man capable of leading our country at a dangerous hour.'

McCain said it was a hard campaign but 'now we move forward together for the good of our party and our nation.'

'We had differences on specific issues, but there was never any doubt about the common philosophy and principles and dedication to the party of Abraham Lincoln, Theodore Roosevelt and Ronald Reagan that we share,' he said.

Romney, 61, and McCain, 71, had battled bitterly over who was the real conservative in the race, culminating in a caustic debate in California on January 30. That was set aside in Boston at Thursday's endorsement ceremony, which was intended to encourage Republican
conservatives long distrustful of McCain to unite behind the all-but-certain nominee.

'I still have my views, the senator has his views, but as a party we come together,' Romney said. 'We can't possibly incorporate all views of all Republicans into one individual,
because we have differing views.' If Romney's 282 delegates were added to McCain's 822, it would give McCain 1,104, putting him within easy reach of the 1,191 needed for nomination. But Romney's delegates are not necessarily bound by his recommendation.

Many conservatives distrust McCain because of his moderate views on illegal immigration and for having originally voted against President George W. Bush's tax cuts.

While Republicans were busily trying to unite, Clinton was trying to stop Obama's wave of momentum. She welcomed news from New Mexico that she had won the party's presidential contest on Feb.5 in a vote so close it took nine days to count and verify.

'I am so proud to have earned the support of New Mexicans from across the state,' Clinton said in a statement, adding she had been awarded 14 of the state's 26 delegates to the party's nominating convention this summer.

Brandishing a pair of blue boxing gloves given to her at a General Motors automobile plant in Lordstown, Ohio, Clinton portrayed herself as a fighter and Obama as someone who makes a lot of speeches that sound good but do not offer solutions.

'That's the difference between me and my opponent. My opponent makes speeches. I offer solutions. It is one thing to get people excited. I want to empower you,' the New York senator said.

Clinton is in for a tough fight. Georgia Rep. John Lewis, a civil rights era icon and one of Clinton's most prominent black supporters said he planned to cast his vote as a 'super delegate' for Obama in hopes of preventing a fight at the Democratic convention, The New York Times reported.

'Something is happening in America and people are prepared and ready to make that great leap,' Lewis was quoted as saying. The super delegates, members of Congress and other leading party officials, can back anyone they wish at the convention.

Clinton, the one-time front-runner for her party's nomination who now finds herself in political peril, intensified her attack as she was forced to scramble for sweeping victories in Ohio and Texas on March 4 and in Pennsylvania on April 22.-Reuters