On the second Tuesday of November this year, Americans will head to the polls to choose their first new president since 2008.

In the 11 months between now and then, that election will hog all the attention and colour every issue across the country.

President Barack Obama promised an active final year in office at his end-of-year press conference before Christmas. But even though he alluded to a lot of "interesting stuff" to come, it is clear that much of what he can do will be circumscribed by the election.

Washington pundits expect almost nothing of consequence to happen in the final few months leading up to November, as political leaders will not risk having their actions influence the polls.

That means all the "interesting stuff" legislatively needs to happen early in the year or be left to the lame duck session - the final congressional session of the year that takes place after a new president has already been chosen.

The one big item outstanding is the mega free trade deal known as the Trans-Pacific Partnership (TPP). Negotiators from the 12 TPP nations, which include Singapore, concluded years of difficult negotiations last October and now look for approval from the various domestic legislatures. Mr Obama has pledged to make it a top priority this year.

Still, the ratification process by the US Congress is considered by far the most fraught among the nations involved. There is little agreement right now on how to push forward the Bill that many in Mr Obama's Democratic Party oppose.

The Republican House and Senate leaders also appear to contradict each other on when to move it. House Speaker Paul Ryan wants a vote to come up quickly while Senate Majority leader Mitch McConnell thinks it should wait.

"It certainly shouldn't come before the election," Mr McConnell said in an interview. "There's significant pushback all over the place."

Every Democratic presidential hopeful opposes the deal.

TPP ratification aside, much attention in 2016 will be paid to Mr Obama's foreign policy - given that presidents tend to look abroad for achievements during a year when little can be done domestically.

The US-China relationship will figure prominently again as both sides continue to face off on issues like cyber security and the South China Sea where China's increasing assertiveness over its territorial claims is an irritant in their ties.

The US is reportedly planning to conduct as many as two freedom-of-navigation operations every quarter in the South China Sea, after its first such voyage in October.

Then there is the fight against the Islamic State in Iraq and Syria (ISIS) which has already become a key feature of the presidential campaign. The crucial question is whether the US will stick to its current "no boots on the ground" policy, especially if the threat of domestic terrorism linked to ISIS does not diminish.

In the election campaign, the real action starts in February, when members of the Republican and Democratic parties start voting to pick their party's nominee for president. The candidates will be officially nominated at the party conventions in July.

The excitement is focused on the crowded field of Republicans, and pundits will be eager to see if billionaire Donald Trump can continue his logic-defying run as favourite. On the Democratic side, the question seems to be not if, but how soon, former secretary of state Hillary Clinton can secure nomination.

Whichever two candidates line up, the stakes are high. Democrats and Republicans are painting very different paths forward for the country and how it interacts with the world. Democrats will likely continue much of Mr Obama's key legacy achievements like strict environmental protection and healthcare reform. Republicans have vowed to dismantle much of these.

With critical challenges coming up both domestically and abroad, 2016 is going to be a big year for the United States.