CHARLOTTE, N.C. -- Former President Clinton used his enduring clout and popularity within the Democratic Party to defend the first term of President Obama and call on the nation to "renew his contract" again in November, despite tough economic times.

"No one could have fully repaired all the damage he found in just four years. But he has laid a foundation for a new, modern, successful economy," Clinton told the cheering delegates.

With the polls showing a close race between Obama and Republican nominee Mitt Romney, the Democrats are eager to connect the prosperous years of the Clinton administration to Obama, who walked onstage to stand arm and arm with his Democratic predecessor at the conclusion of his remarks.

(Watch highlights from Clinton's speech above, or view the full speech below)

"If you want a you're-on-your-own, winner-take-all society, you should support the Republican ticket. If you want a country of shared responsibilities -- we're-all-in-it-together society, you should vote for Barack Obama and Joe Biden," Clinton said.

Like no other speaker who has appeared at the convention so far, Clinton tackled the sour economy head-on, winding his way through a 50-minute speech that credited Obama for stopping a much worse economic disaster from happening.

"In Tampa, the Republican argument against the president's reelection was pretty simple: We left him a total mess, he hasn't cleaned it up fast enough, so fire him and put us back in."

Clinton's remarks made the strongest case yet for Obama, a man who was his political foe four years ago when he defeated wife Hillary Clinton for the Democratic nomination.

Clinton said he understood that "Americans are still angry and frustrated with the economy."

But he shielded Obama from blame, and said Romney would make things worse.

"We simply cannot afford to give the reins of government to someone who'll double down on trickle down."

Clinton's appearance lifted the convention after a tumultuous day in which delegates argued over the party's platform positions on Israel and God.

Clinton changed the subject back to Obama, promoting his accomplishments like health care reform, energy policy and plan to reduce the debt.

He delivered a scathing critique of the GOP platform and rebutted Republican attacks like a skilled trial lawyer. He broke down the argument made by Republican vice presidential nominee Paul Ryan that the Democratic health care plan would rob Medicare of $716 billion.

"I didn't know whether to laugh or cry," Clinton said. "You see, that $716 billion is exactly the same amount of Medicare savings Congressman Ryan has in his own budget."

"When times are tough, constant conflict may be good politics, but what works in the real world is cooperation," Clinton said. "Unfortunately, the faction that now dominates the Republican Party doesn't see it that way. They think government is the enemy and compromise is weakness."

Clinton also tackled the Romney budget plan, telling the audience "the numbers don't add up."

The crowd often roared with delight during Clinton's remarks.

But that cheering was topped when Obama emerged onstage, waving to the crowd with one arm, the other wrapped around a man whose presidency delivered four surplus budgets, millions of jobs and general economic prosperity.