Former president Bill Clinton is set to take aim at the Republican party when he delivers the keynote address Wednesday night at the Democratic National Convention.

In excerpts of his speech released in advance, Mr. Clinton says the Republicans left the United States and President Barack Obama with a “total mess.” He also says electing Republican presidential candidate Mitt Romney will lead to, what he calls, a “you're-on-your own, winner-take-all society.”

Mr. Clinton also credits President Obama with laying the foundation for a “more modern, more well-balanced economy that will produce millions of good new jobs, vibrant new businesses, and lots of new wealth.”

Mr. Clinton remains a popular figure among many Americans who recall the economic prosperity during his two terms in office in the 1990s. He will will formally place the Mr. Obama's name up for nomination during the nationally televised address.

U.S. President Barack Obama arrived in Charlotte, North Carolina earlier Wednesday his party's national convention.

Hours earlier, party officials looked at Thursday's weather forecast and decided to move his night-time nomination acceptance address from an outdoor football stadium because of concerns about rain. The president will instead speak in the much smaller, 20,000-seat indoor arena where the remainder of the convention is being staged.

Democratic officials said they feared the possibility of rainstorms during the speech. Mr. Obama's Republican opponents said the real worry for his supporters was that the president might not attract enough people to fill the 74,000-seat stadium.

In a statement, convention organizer Steve Kerrigan said the group shared the “disappointment of over 65,000 people” who had signed up for credentials to attend the outdoor event. He said Mr. Obama would speak to them during a Thursday conference call.

Mr. Obama's opponent in the November 6 election is Republican Mitt Romney, a one-time venture capitalist and former governor of Massachusetts. Surveys of voters show the two candidates in a virtual tie nine weeks ahead of election day.