At long last, President Biden has made it official that he is running for reelection in what he portrayed as “a generational moment for Americans across the country to stand up and fight for our democracy and freedoms.”

But despite the characteristic optimism that pervaded his announcement, the president’s 2024 political prospects are far from ideal.

His job approval is stuck in the low 40s, and he is regarded unfavorably in many states he needs to win. Most Americans don’t want him to run.

Moreover, he may face a prospect that could prove almost as difficult for him as losing – and that is winning. Because he might luck into having Donald Trump as a repeat opponent, the president could win a second term.

But given the second-term records of most reelected presidents back to Thomas Jefferson, that prospect ought to have given him some pause before he decided to make Tuesday’s announcement.

Richard Nixon was nearly impeached and forced to resign. Ronald Reagan became enmeshed in a scandal for selling arms to free hostages. Bill Clinton was impeached for lying about an affair with a White House intern. George W. Bush became bogged down in a war launched under false pretenses and the worst domestic recession in decades.

And though Barack Obama survived his second term without major scandal, policy disaster or recession, congressional Republicans were able to block most of his second-term initiatives.

They’re not the only ones. Both Harry Truman and Lyndon Johnson had such difficult full terms after inheriting the office that they decided against seeking reelection because of the prospect they’d lose. Woodrow Wilson overreached his political mandate – and then suffered a debilitating stroke. Jefferson’s was marked by an ineffective, unpopular embargo of warring European nations.

Even Dwight Eisenhower, one of the most successful post-World War II presidents, had a difficult second term in which a sweeping Democratic congressional victory foreshadowed the GOP’s 1960 loss of the presidency.

To be sure, it’s not all been bad for second-term presidents.

Reagan won enactment of a major tax bill and the country’s last bipartisan immigration bill. Clinton worked with congressional Republicans to pass a tax cut bill that led to the first balanced budget in 30 years. Besides maintaining his signature Affordable Care Act, Obama helped reach an agreement to curb Iran’s nuclear program and an international climate change treaty, though Trump revoked both.

Some Democratic strategists believe that, if Trump is again his Republican rival, Biden would not only win but also have the same narrow congressional control as in the first part of his term. That could let him build on previous legislative triumphs and confirm more Democratic judges, including to the Supreme Court.

Other Democrats think another Trump nomination could produce an even bigger Democratic triumph.

But those are still optimistic scenarios for Biden, given that the country remains closely divided ideologically and Trump’s tight hold on the Republican electorate would likely ensure him close to the 47% of the two-party vote he got in 2020.

More likely, if Biden does win, it would be by a sufficiently narrow margin that he would be lucky to win one house, let alone two.

Republicans currently hold the House by just four seats, but 14 districts with GOP members voted in 2020 for Biden. A Biden presidential victory could easily flip the House for the third election in the last four.

The Senate is more problematic. Democrats hold a 51-49 majority with the votes of three independents. But almost all key 2024 races are for seats held by Democrats, meaning they’d have to pull another inside straight to win narrow control for the third election in a row.

What would that mean for a reelected President Biden?

If Democrats win the House, they would be able to shape legislation though Biden’s first term has shown that, with a closely divided Senate, compromises are generally necessary.

A Democratic Senate would enable the president to win confirmation of most executive choices like Cabinet members and federal judges, a major priority for the Democrats as they seek to counter the impact of the large number of Trump-nominated conservative judges.

Most important, it would give Biden and the Democrats a realistic chance of winning confirmation of a Supreme Court justice if a vacancy occurs. At present, the court has six Republican nominees and just three Democrats.

But if Biden lost the Senate, he would have a very difficult time. He could probably win confirmation of most Cabinet picks, assuming he makes judicious choices. But the GOP could make it very hard for him to win confirmation of federal judges with partisan backgrounds.

A Supreme Court vacancy could produce a real mess.

The true presidential nightmare would be to lose both houses, forcing Biden to rely on vetoes to block Republican-passed legislation, rather than trying to pass his own agenda. He’d likely concentrate on foreign policy where a president has more leeway. But even there, congressional Republicans could complicate his life.

In seeking a second term at the age of 80, Biden is not only gambling that the political environment will enable him to win – and to govern – but that he will be able to maintain good health.

Second terms are not easy, even under the best of circumstances, and Biden will need some luck to have those.