Bill Clinton, America's 42nd president, takes center stage at the Democratic National Convention Wednesday night, when he will tell a national audience why he believes President Barack Obama should be reelected.

Mr. Clinton — who left office after two terms nearly 12 years ago — is expected to direct his message to middle-class Americans. His advisors say he will seek to persuade viewers that President Obama's economic policies offer the country its best chance to reverse the economic downturn that began six years ago with the housing sub-prime mortgage crisis.

In a new television advertisement backing Mr. Obama, Mr. Clinton says “this election to me is about which candidate is more likely to return us to full employment. This is a clear choice,” he says.

Revered in Democratic circles for his political savvy, Mr. Clinton is said to have warmly welcomed the invitation to place Mr. Obama's name in nomination — something no former president has done before.

Analysts say the Clinton-Obama political divide of four years ago — triggered by a bitter primary fight between the future president and Bill Clinton's wife, Hillary — has largely healed since Mr. Obama's 2008 win. Since then, Hillary Clinton has served as the U.S. Secretary of State and garnered generally high marks for her performance.

Clinton supporters are quick to point out that the former president presided in the 1990s over the last period of sustained U.S. economic growth. As such, party leaders are hoping his formal endorsement Wednesday night will boost Mr. Obama's popularity during a sustained period of more than eight percent unemployment.