WASHINGTON (AP) — President Barack Obama set up high-stakes clashes over guns, immigration, taxes and climate change in a State of the Union address that showcased a newly re-elected president determined to mark his legacy, facing off against a deeply divided Congress with Republicans eager to rein him in.

At the center of it all was a fight over the very role of government, with Obama pushing a raft of new initiatives to improve preschool programs and voting, boost manufacturing and research and development, raise the minimum wage and lower energy use. "It is our unfinished task to make sure that this government works on behalf of the many and not just the few," he said.

Republicans who control the House and hold enough votes to stall legislation in the Senate were just as quick to declare that the government helps best by getting out of the way.

"More government isn't going to help you get ahead. It's going to hold you back. More government isn't going to create more opportunities. It's going to limit them," Sen. Marco Rubio, R-Fla., said in the Republican response Tuesday night. "And more government isn't going to inspire new ideas, new businesses and new private sector jobs. It's going to create uncertainty."

Uncompromising and aggressive, Obama pressed his agenda on social issues and economic ones, declaring himself determined to intervene to right income inequality and boost the middle class. He called on Congress to pass comprehensive immigration reform with a pathway to citizenship for 11 million illegal immigrants, far-reaching gun control measures and a climate bill to cut greenhouse gas emissions. He threatened to go around Congress with executive actions on climate change if it fails to act.

But Obama cannot count on willing partners on those issues, any one of which could tie Congress in knots for months with no guarantee of success. Gun control, which Obama made a focus of his speech, faces dim prospects on Capitol Hill. The prospect for immigration legislation is better, but no sure thing. Climate change legislation is given no chance of success.

And Obama addressed relatively briefly the looming fiscal crises confronting the nation and inevitably sucking up oxygen on Capitol Hill — the deep automatic spending cuts or "sequester" to take effect March 1, followed by the government running out of money to fund federal agencies March 27. He made clear he will continue to press for the rich to pay more in taxes, a position Republicans have rejected.

Republicans, meanwhile, made clear they're in little mood to cooperate.

"We are only weeks away from the devastating consequences of the president's sequester, and he failed to offer the cuts needed to replace it," House Speaker John Boehner, R-Ohio, said in a statement. "In the last election, voters chose divided government which offers a mandate only to work together to find common ground. The president, instead, appears to have chosen a go-it-alone approach to pursue his liberal agenda."

Earlier Tuesday, in a meeting with television correspondents and anchors, Boehner said immigration is about the only item on Obama's list that has a chance of passing this year. He said the president is more interested in getting a Democratic majority in both chambers next year and said he doesn't believe Obama "has the guts" to take on liberals in his party over spending cuts.

Obama did reiterate his willingness to tackle entitlement changes, particularly on Medicare, though he has ruled out increasing the eligibility age for the popular benefit program for seniors.

"Those of us who care deeply about programs like Medicare must embrace the need for modest reforms — otherwise, our retirement programs will crowd out the investments we need for our children and jeopardize the promise of a secure retirement for future generations," he said.

"But we can't ask senior citizens and working families to shoulder the entire burden of deficit reduction while asking nothing more from the wealthiest and most powerful."

On immigration, a bipartisan group of negotiators in the Senate is working to craft legislation embracing Obama's call for a pathway to citizenship for illegal immigrants but making such a path contingent on first securing the border, a linkage Obama has not supported.

But there's no guarantee the Senate bipartisan plan will find favor with the full Senate or the House. The first test may come Wednesday morning when the Senate Judiciary Committee opens its hearings on a comprehensive immigration overhaul. Deep fault lines emerged even before the hearing began, with a leading committee Republican, Sen. Jeff Sessions of Alabama, calling Obama's remarks on immigration "deeply troubling."

"The biggest obstacle we face to reform is this nation's failure to establish lawfulness in the system," Sessions said. "The president's immigration plan meets the desire of businesses for low-wage foreign workers while doing nothing to protect struggling American workers."

The president implored lawmakers to break through partisan logjams, asserting that "the greatest nation on earth cannot keep conducting its business by drifting from one manufactured crisis to the next."

"Americans don't expect government to solve every problem," he said. "They do expect us to forge reasonable compromise where we can."