WASHINGTON (AP) — Declaring the American dream under siege, President Obama delivered a populist challenge Tuesday night to shrink the gap between rich and poor, promising to tax the wealthy more and help jobless Americans get work and hang onto their homes. Seeking re-election and needing results, the president invited Republicans to join him but warned, “I intend to fight.”

In an emphatic State of the Union address, Obama said ensuring a fair shot for all Americans is “the defining issue of our time.” He said the economy is finally recovering from a deep and painful recession, and he will fight any effort to return to policies that brought it low.

“We’ve come too far to turn back now,” he declared.

Obama outlined a vastly different vision for fixing the country than the one pressed by the Republicans confronting him in Congress and fighting to take his job in the November election. He pleaded for an active government that ensures economic fairness for everyone, just as his opponents demand that the government back off and let the free market rule.

Obama offered steps to help students afford college, a plan for more struggling homeowners to refinance their homes and tax cuts for manufacturers. He threw in politically appealing references to accountability, including warning universities they will lose federal aid if they don’t stop tuition from soaring.

Standing in front of a divided Congress, with bleak hope this election year for much of his legislative agenda, Obama spoke with voters in mind.

“We can either settle for a country where a shrinking number of people do really well, while a growing number of Americans barely get by,” Obama said. “Or we can restore an economy where everyone gets a fair shot, everyone does their fair share, and everyone plays by the same set of rules.”

A rare wave of unity splashed over the House chamber at the start. Rep. Gabrielle Giffords, survivor of an assassination attempt one year ago, received sustained applause from her peers and cheers of “Gabby, Gabby, Gabby.” She blew a kiss to the podium. Obama embraced her.

Lawmakers leapt to their feet when Obama said near the start of his speech that terrorist leader Osama bin Laden, killed by a raid authorized by the president, will no longer threaten America.

At the core of Obama’s address was the improving but deeply wounded economy — the matter still driving Americans’ anxiety and the one likely to determine the next presidency.

“The state of our union is getting stronger,” Obama said, calibrating his words as millions remain unemployed. Implicit in his declaration that the American dream is “within our reach” was the recognition that, after three years of an Obama presidency, the country is not there yet.

He spoke of restoring basic goals: owning a home, earning enough to raise a family, putting a little money away for retirement.

“We can do this,” Obama said. “I know we can.” He said Americans are convinced that “Washington is broken,” but he also said it wasn’t too late to cooperate on important matters.