Senator Hillary Clinton is challenging her Democratic Party presidential rival, Senator Barack Obama, to a debate. The call is part of the escalating rhetoric between the two as they campaign in the central state of Indiana. VOA's Kent Klein reports from Washington.

Clinton is trailing Obama in delegates and in the popular vote, and she has been putting pressure on him to hold more debates before the May 6 primary elections in Indiana and the Southern state of North Carolina. On Saturday, Clinton called for a 90-minute debate without a moderator. "I hope we will be able to have a good old-fashioned Lincoln-Douglas debate right here in Indiana, so that you can see for yourself to make the decision about who our next President should be," she said.

The style of debating where each side presents an argument gets its name from the 1858 debates in Illinois between U.S. Senate candidates Abraham Lincoln and Stephen Douglas.

Obama's campaign aides say they are studying the debate request. Obama has complained that in the last debate, on April 16th, the moderators focused too much on political trivia and too little on real issues.

Clinton told a crowd in South Bend, Indiana Saturday she is focusing on the substance of the issues, while Obama is relying on style. "I have been very specific across Indiana and America to talk about solutions, because my campaign is about solutions, not speeches. It is about working to make the changes that we know we must have," she said.

At a rally in Anderson, Indiana, Obama responded to critics who say he has not been tough enough in responding to Clinton's verbal jabs. "I am not interested in fighting people just for the sake of scoring political points or getting on the cable news shows. If I am going to fight somebody, it is going to be fighting over the American people and what they need. I will fight for health care. I will fight for a good education system. I will fight to make sure that people have good jobs and good wages. I will fight to the death to make sure that America is safe. Those things I will fight for. That is what I will fight about," he said.

Polls show that Obama has a substantial lead in North Carolina, and that in Indiana, the two Democrats are either even or Obama has a slight lead.

The presumptive Republican nominee, Senator John McCain, did not make any campaign appearances Saturday, after appearing in the Southern state of Arkansas Friday with former Governor Mike Huckabee, a one-time rival for the Republican presidential nomination.