The top Republican presidential candidates sparred over immigration, the economy and national security in a debate broadcast by Fox News Television. VOA's Brian Wagner reports the debate comes ahead of the latest round of primary votes.

Republican candidates tried to tailor their messages to voters in Michigan and South Carolina, as the two states prepare for primaries in coming days. Analysts say economic stability and job losses are worrying voters in the Midwestern state of Michigan, while many in South Carolina are concerned about illegal immigration.

Opinion polls show Senator John McCain leading the field of Republican hopefuls following his victory in the New Hampshire primary this week.

In Thursday's debate in South Carolina, McCain emphasized his commitment to conservative ideals, similar to those held by former President Ronald Reagan.

"We have to return to those principles of less government, lower taxes, strong family values, strong national defense, and those [values] that made us the Reagan revolution that brought about a new dawn of a new day in America," he said.

Former Massachusetts Governor Mitt Romney is trailing McCain, according to polls in Michigan, which holds its primary next Tuesday. Romney told voters that he was a better choice for president than McCain and elected officials currently in Washington.

"I keep hearing the same thing, which is that Washington is broken," he said. "Washington has made promises to America it has not kept, and it seems incapable of dealing with the challenges we face globally and here at home."

Romney is in a close race for second place in the Republican field with former Arkansas Governor Mike Huckabee. Huckabee said he has the experience to counter a possible economic recession and help expand opportunities.

"During my tenure, we had the lowest unemployment records in the history of the state," he said. "And we created a record number of jobs, and jobs that paid more money than the jobs they replaced."

Former Senator Fred Thompson was expected to get a boost from the debate in South Carolina, where he has been campaigning heavily. Thompson told voters that he has one of the toughest proposals to fight illegal immigration by reinforcing the nation's borders.

"We need to be a nation of high fences and wide gates and we get to decide when to open the gate and when to close it," he said.

Former New York Mayor Rudy Giuliani has been trailing the top contenders in the race so far. On Thursday, he invoked the memory of former President Reagan to emphasize his strong position on national security issues.

"I think peace through strength that Ronald Reagan proposed to deal with the Cold War, is similar to what we have to do with this terrorist war against us," he said. "That is why my first commitment to the American people is to be on offense against the terrorists."

On the Democratic side, Senator Barack Obama on Thursday received an important endorsement to his candidacy, as he battles for the lead with Senator Hilary Clinton. Senator John Kerry, who lost to president Bush in the 2004 election, said he backs Obama as the party's candidate.