Washington (CNN) As Donald Trump reeled off his debut State of the Union address , it felt like the tumult and anger and chaos of the last few years never happened.

For after tearing at America's divides to win and wield power, the President used his big televised moment on Tuesday night to pose as the great uniter.

Summoning all the pageantry of his office, in a scripted speech which mixed oratory with praise for inspirational American heroes in the first lady's gallery , Trump made a coherent, though controversial case for his presidency, declaring there had never been a better time to live the American dream.

But as the last standing ovation subsided, questions remained: How many hours, or days, will Trump's optimistic vision and open hand for bipartisan compromise last, given his more usual erratic and confrontational behavior?

And will Trump win any political benefit from an empathetic appearance given controversies that he can't control, including the corrosive daily toll of the Russia investigation that is now reaching deep into his White House?

Forge common ground

Repeatedly on Tuesday, Trump offered to forge common ground with Democrats on emotive issues such as immigration or the meaning of patriotism, that were a departure from the radioactive rhetoric he had used in the past.

He even offered to work on issues important to liberals like infrastructure, family leave and criminal justice reform.

But then he used language that could inflame and offend his opponents, in an example of the bulldozing political method that undercuts his calls for national unity and likely makes compromise on the most difficult issues unlikely.

Commanding center stage, gripping the lectern in the House of Representatives, Trump, his jaw set, in a trademark dark suit and bold blue tie, looked every inch a president, striking a contrast with his often unpredictable behavior outside formal settings that has crashed against political norms.

"Tonight, I call upon all of us to set aside our differences, to seek out common ground, and to summon the unity we need to deliver for the people we were elected to serve," Trump said.

A year after decrying the "American carnage" of lost jobs and ruined lives in his stark inaugural address, Trump effectively declared it was morning in America again, recalling the upbeat economic message of Ronald Reagan.

It may be that in the short-term at least, that the President's calls for bipartisanship and compromise strike a chord with the public, which is weary of years of bitterly partisan politics.

In a snap CNN/SSRS poll, 48% of people who watched the speech reacted very positively, 22% reacted positively, and 29% had a negative response. Such polls do not offer an intricate national picture because they tend to sample people more well disposed to the President at the time.

Republican leaders poured praise on their President.

"I thought he was outstanding," said Senate Majority Leader Mitch McConnell, when asked for his reaction to the address by a President whose frequent policy reversals have often infuriated the GOP Senate leader.

House Majority Leader Kevin McCarthy said he thought the President came across as a "leader trying to bring both parties together."

A new dawn

Yet Trump's proclamation of a new dawn was darkened by the political tumult raging outside the Capitol, as the Russia scandal races to a crisis point , and given his own history as a President who has often torn at political, cultural and societal divides as a tool of government.

It was no surprise that Trump could deliver a scripted, sweeping speech and master the theatrics of a national moment. It's a given that his performance will bolster the ultra-loyal supporters in his political base.

But it seems far less likely that his calls for compromise and civil demeanor mark a turning point in his presidency. Last year, his joint address to Congress contained similar soaring calls for unity delivered with a presidential flourish.

Days later, Trump tweeted an explosive claim that President Barack Obama had wiretapped him while he was a candidate, immediately killing off any lingering political dividend of his first big address to Congress.

And the experience of the last year suggests that the authentic version of Trump is not the one on display on Tuesday night -- but the unrestrained, sometimes profane and raging personality on display on Twitter and elsewhere.

"He says in his speech he is offering an open hand," said CNN political analyst David Axelrod, a former adviser to Barack Obama. "The question is whether tomorrow morning he offers the brass knuckle again."

In its tone, the address by Trump, the most unconventional of presidents, was packed with the calls for bipartisanship, political give-and-take, and claims of soaring political achievements that are typical of all such occasions.

Yet in substance, and despite his calls for compromise, Trump appeared to offer few modifications to policies on immigration, the environment, health care and taxation that have already alienated his opponents.

Much of his rhetoric appeared to anger Democrats, many of whom looked on with stony expressions. The message seemed to be, that if there is to be compromise, it will be on his terms only.

On immigration, for instance, Trump offered a plan with four pillars to safeguard 1.8 million undocumented people brought to the United States illegally as kids, but laid out tough conditions on family migration and diversity lotteries.

His remark that "Americans are dreamers, too" and a long passage about MS-13 gang violence appeared to some observers to equate immigrants with criminals.

"He was selling sweet-tasting candy with poison in it," CNN political commentator Van Jones said.

Unfolding in a vacuum

Trump's presentation sometimes appeared to unfold in a vacuum as he voiced the platitudes and expressions of good feeling that are always uttered by Presidents in the State of the Union address.

This after all, is a President who has torn at the institutional fabric of the nation, waging personal feuds against the judiciary, the FBI and the media and who has often appeared to chafe against the constitutional constraints on his power.

His magnanimity seemed incongruous, given that he had previously reportedly lambasted African nations as "shitholes," complained that he could not order the Justice Department to pursue Hillary Clinton and equivocated over condemning neo-Nazi demonstrators after the Charlottesville riots last year.

As he turned to his achievements, Trump made an effective case for his economic management, lauding record stock market highs, robust job creation, new factory openings, company bonuses, new car plants and trade deals in the process of being renegotiated.

"This is all news that Americans are unaccustomed to hearing -- for many years, companies and jobs were only leaving us. But now they are coming back," Trump said.

For an hour or so at least, Trump escaped the grim shadow of the Russia investigation, that has pursued him every day of his presidency.

But he made no mention of the finding by US intelligence agencies that Russia meddled in the 2016 election and favored his campaign. Escalating attempts by Trump and his allies on Capitol Hill and in conservative media to undermine the investigation by special counsel Robert Mueller are certain to actively undermine the trust and unity that he was trying to foster on Tuesday night.

Hours before his speech, Trump's lawyers pushed back on the notion that the President will testify to Mueller's probe, despite his statement that he would love to do so last week.

The coming days will also decide whether Trump managed on Tuesday to fulfill political objectives at the beginning of a crucial midterm election year in which Democrats have high hopes of winning back the House, in a scenario that could cripple the Trump presidency. Droves of Republicans, in the knowledge that parties of unpopular first term presidents often take a hit, have already announced their retirements.

The President went into the night with an approval rating at around 40%, with critical votes looming on funding the government, raising the debt ceiling and on immigration, needing Democratic votes in the Senate.

In the immediate aftermath of his speech, which most key Democrats watched in stony silence, it was not clear that he had made any significant progress.