– President Obama launched his final year in office with a valedictory State of the Union address Tuesday night that painted a portrait of a prosperous and secure America but warned of peril ahead if the country can't break the political logjam in Washington.

His final rendition of the annual speech focused more on broad themes than on ­ambitious new plans, and was the shortest of his tenure.

He praised America for its opportunity and security, and cited a rising standard of living and growing efforts to preserve the planet — all achievable, he said, under the course he has set in his seven years in office.

Still "it will only happen if we can have rational, constructive debates," he told a joint session of Congress. "It will only happen if we fix our politics."

In a rare admission of fault for the Democratic president, he acknowledged that he is not blameless for the hardened, hyperpartisan political ­atmosphere of his presidency, a responsibility of leadership he has never managed to shoulder despite the aspirations of his historic quest for the office.

In a speech following the New Hampshire primary nearly eight years ago, Obama stirred hopes of national unity with his declaration that "we are one people, we are one nation."

But the country has moved toward more rigid partisan lines and intransigence in Congress and in popular opinion during the Obama era. And with just one year left to fulfill his promises, Obama sees the division as a threat — not just to his political agenda, but to his political legacy.

Obama did not shy away from soaring words, and even increased altitude with the ­historic allusions and grand rhetoric that first brought him to national attention.

America has been through big changes before, he said, recalling wars and depression, the influx of immigrants and movements for civil and worker rights. Americans overcame their fears, he said.

"We did not, in the words of Lincoln, adhere to the 'dogmas of the quiet past,' " he said. "We made change work for us, always extending America's promise outward, to the next frontier, to more and more people. And because we did — because we saw opportunity where others saw only peril — we emerged stronger and better than before."

He did not mention any particular Republicans he thinks may be clinging to those old dogmas and acting on their fears. But the race to choose his successor has weighed on the White House in recent months, with Obama himself expressing growing concern about what he sees as fear-inducing statements from some GOP presidential candidates, including anti-immigrant rhetoric from front-runner Donald Trump.

"There is this doubling down on a dark vision on the state of the American economy and the state of America's leadership around the world that he believes is just not true," said Ben Rhodes, deputy national security adviser who helped shape the speech.

A Democratic successor would be able to protect more of those achievements, including Obama's withdrawal of U.S. ground troops from wars in the Middle East, and a new insistence on building up allies and partner countries to manage their own crises without a huge U.S. military presence.

Obama laid out his plans for building on his legacy in words that rang familiar after his years in office.

The country must give everyone a "fair shot" in the new economy and make technology work for people and not against them, he argued.

He talked about preparing the workforce for the changing marketplace, and pushing for universal prekindergarten and college affordability while also safeguarding Social Security and Medicare. He vowed to support Vice President Joe Biden's project to cure cancer.

On foreign policy, he implicitly rejected the choice that his critics offer between isolation from the global community and sending U.S. troops to occupy foreign countries.

"Leadership means a wise application of military power, and rallying the world behind causes that are right," he said, citing the U.S. role in shaping the recent international climate agreement and response to the Ebola crisis in Africa.

"That's strength. That's leadership," he said.

As he neared the end of his speech Obama veered away from policy altogether, rising into a sermon-like oratory on the state of American politics.

He decried the practice of drawing congressional district maps by dominant state political officials to favor their parties and blamed "dark money" for empowering millionaires and corporations over average citizens.

Beyond that, Obama said, Americans are out of practice in working out differences.

"A better politics doesn't mean we have to agree on everything," he said. "Our Founders distributed power between states and branches of government, and expected us to argue, just as they did, over the size and shape of government, over commerce and foreign relations, over the meaning of liberty and imperatives of security.

"But," he said, "democracy does require basic bonds of trust between its citizens."