Obama liberated? Five things to watch in State of the Union.

President Obama delivers his sixth State of the Union address Tuesday night, but it’s a new ballgame. Republicans now control both houses of Congress, and Mr. Obama’s veto pen is ready.

Instead of seeming chastened by his party’s reduced status, with slim hopes of enacting any major Democratic initiatives in his final two years in office, Obama is buoyant. The economy is rebounding, his job approval has gone up, and he’s pushing bold proposals that please his party’s base and leave Republicans indignant.

“Losing control of both houses does liberate him to a considerable degree,” says Michael Waldman, former chief speechwriter for President Clinton and president of the Brennan Center for Justice at New York University.

Obama has spent the past two weeks touring the country and delivering “SOTU spoilers,” laying out policy ideas one by one instead of saving them all for the State of the Union, a.k.a. SOTU. From proposals for free community college and paid family and medical leave to higher taxes on the wealthy, the president is doubling down on his longstanding goal of boosting the middle class.

But as Obama enters the final quarter of his presidency, he also has an eye on his legacy – and on the 2016 presidential race now taking shape. Hillary Rodham Clinton, strongly favored to be the Democratic nominee, may have more at stake than anyone in the House chamber Tuesday night. (The speech begins at 9 p.m. Eastern time.)

Here are five themes to watch for in SOTU 2015:

Obama’s case for the economy. When Obama took office Jan. 20, 2009, the economy had plunged into a deep recession. Six years later, the recovery looks robust: Unemployment is down to 5.6 percent, economic growth in the third quarter of 2014 came in at 5 percent, gas prices are down, and the stock market is breaking records.

“America is now in a position to really turn the page,” Obama said in a pre-SOTU video released Monday night.

But wage growth remains stagnant, and the gap between the haves and have-nots continues to grow. Many of Obama’s new initiatives, which he will review Tuesday night, are aimed at boosting the middle class – both those already there and those who want to get there. Education will be a central theme. His proposal to raise taxes on the wealthy (and cut taxes for the middle class) is aimed at paying for his initiatives. But the Republicans have already rejected the idea. The White House knew they would, so the proposal is seen as a political play.

Obama’s mixed message to Republicans. Not only will the president issue a series of proposals Republicans have no intention of pursuing, but he also surely will remind Republicans of his veto power. In six years, he has issued only two vetoes. This month alone, he has threatened five more, including on bills to authorize the Keystone XL pipeline, new sanctions on Iran, and an effort to overturn his executive actions deferring deportation of illegal immigrants.

But Obama’s relationship with congressional Republicans isn’t purely adversarial. Some Republicans favor his diplomatic opening to Cuba. Obama’s proposals to enhance national cybersecurity and protect personal data also have bipartisan support. There are areas – particularly on international trade – where the president is more in sync with the GOP than with his own party.

The newly empowered Republicans need to show they can govern, and so watch Obama work to take advantage of that opportunity.

“The American people don’t expect this era of partisan warfare to end abruptly, but they are looking for a break in the storm,” says William Galston, a scholar at the Brookings Institution and a former Clinton White House policy adviser. “The one reason there may be some possibilities [for cooperation] in the first nine months of 2015 is that neither party wants to bear the sole onus for the total failure of the third Congress in a row to get anything done.”

Obama’s mixed message to Democrats. For the most part, Obama will be all Democrat all the time Tuesday night. And in proposing a restructuring of the tax code that goes after inherited wealth and raises the tax rate on capital gains for the wealthiest Americans, he is taking a bow to the liberal Elizabeth Warren wing of the Democratic Party.

But Obama’s desire to conclude international trade deals that Democrats oppose is a sore point within the party, and Obama will choose his words carefully.

“You don’t poke a stick in your own party’s eye on national TV,” Mr. Galston says. “But what you can do is emphasize your willingness to cooperate and compromise in the areas where that’s possible.”

In recent days, Galston says, the White House has begun to understand how little Democratic support there is for Obama’s trade agenda in Congress. The withdrawal of Antonio Weiss as Obama’s choice for a top Treasury Department post because of liberal objections to his Wall Street background shows the growing power of that wing of the party.

The case for Obama’s legacy. The unspoken message of Tuesday’s address will be that he’s no lame duck.

“My presidency is entering the fourth quarter. Interesting stuff happens in the fourth quarter,” Obama said last month.

After six years in power, he has a legacy to defend and build on. The Affordable Care Act survived its first year of implementation. By the third quarter of 2014, the uninsured rate among non-senior adults has declined to 15 percent, down from 20 percent in the second quarter. That translates to 9.5 million more people with health coverage. But the future of the law rests once again with the Supreme Court, which will hear a case in March that threatens the federal subsidies for many recipients. If the Obama administration loses, the law will be gutted.

The dramatic rise of the right to same-sex marriage, now legal in 36 states, is another legacy of the Obama years. And its future also sits in the Supreme Court, which will decide by June whether gay couples across the country have that right.

Some of the justices will be present at Obama’s address, though any appeal by the president on those issues will be aimed at a general audience. Both, he may say, have become a part of the fabric of American life, and need to be protected and expanded.

The biggest element of Obama’s legacy will be the economy, and he is expected Tuesday night to deliver his most full-throated celebration of its recovery since taking office. If the recovery continues, and particularly if the middle class feels less squeezed, that will go a long way toward solidifying positive assessments of his tenure.

His impact on Hillary Clinton. It’s too soon for the SOTU to have direct bearing on the 2016 presidential race. Wait a year for that. But in his speech Tuesday night, expected to be viewed by 30 million Americans, Obama will nevertheless be setting the table for former Secretary of State Clinton, who is expected to run for and win the Democratic nomination.

As with his own legacy, the state of the economy will bear directly on Clinton’s chances. Obama’s agenda will shape how voters perceive Clinton, as the heir to his party’s leadership.  And so too will Obama’s handling of the increasingly vocal populist wing of the Democratic Party. Clues to that dynamic are likely to be on display Tuesday night.

“It seems to me that one of the positive things he could do for the party – and incidentally for Hillary – would be a little more populist tinge to his rhetoric, especially on health care and [the banking law known as] Dodd Frank,” says Cal Jillson, a political scientist at Southern Methodist University in Dallas.