The success of President Obama's next four years in office -- and his legacy -- depends on his ability to deliver on immigration reform, new gun laws, a green energy boom and perhaps above all, a fiscal blueprint that could loosen the stranglehold on governing in Washington.

Set to give his second inaugural address Monday, Obama will almost certainly tout his accomplishments over the last four years while trying to build momentum for an agenda with an ever-shrinking time schedule.

After vowing to bridge the political divide four years ago -- a promise he was unable to keep -- Obama now faces a political environment as toxic as any in recent memory, an obstacle that could derail his top priorities.

In his first term, Obama instituted the most sweeping changes to America's health care system since Medicare was created in 1965. Now in the process of winding down two costly wars, Obama said his second term will focus mainly on domestic issues, including reducing gun violence and instituting comprehensive immigration reform.

Republicans have shown a willingness to negotiate on immigration policy after taking a beating among Latino voters in the 2012 elections. But gun control seems like a non-starter in the GOP-controlled House. And Republicans have shown little desire to accommodate the president until they settle differences over federal spending and taxes.

"You have 16 months max to accomplish a domestic agenda," said veteran Democratic strategist Christopher Lehane. "And the body politic in D.C. is like a snake. It can only swallow one thing at a time. The reality is you're likely going to have to deal with the fiscal piece before the others move through the system."

As much as Obama wants to frame his second term with lofty benchmarks, just as important is the imprint of his policies enacted during the first term, particularly his health care reforms.

"There are three problems for presidents in their second terms: an agenda left over from the first term, time and loss of ability to persuade members of Congress in the latter part of your term," said presidential scholar Martha Joynt Kumar. "One of the ways a second-term president can increase his effectiveness is to focus attention on the implementation of legislation he has already gotten passed."

And then there's the unpredictable. Obama largely benefited from developments on the foreign stage, especially the killing of al Qaeda leader Osama bin Laden. However, the volatility of the Arab Spring could mire the final years of his presidency.

Presidential second terms can be hamstrung by executive overreach, and Obama launched his with a ferocity only hinted at during his first four years. Yet, the economy that was a drag on his presidency is little improved and could dominate his last four years.

"Our economic growth has been so small," said former Mississippi Gov. Haley Barbour. "Here's a president who ran for re-election and could not run on his own record. Most Americans know you can't spend yourself rich -- and the government can't either. To claim a mandate for new, big-government solutions is quite a stretch."