Hillary Clinton has a net favorable rating that is unprecedentedly bad for a non-incumbent major party presidential nominee. The good news for Democrats is that the Republican frontrunner, Donald Trump, does much worse on this score (as does Ted Cruz). So there's no need to panic.

Still, as Barack Obama's approval rating drifts up in 2016 it's hard not to notice that the party isn't exactly fielding its strongest talent. Most Americans approve of the job Obama is doing as president. He is viewed more favorably than Clinton, and, in a pretty hard-to-beat combination, he is both considerably younger than Clinton and also manages to edge her out in experience and qualifications.

Not only would he be a stronger nominee, his presence on the ballot would give a greater coherence to the election.

Obama hangs over every moment of the 2016 race. It would make a lot more sense for him to directly face his critics on the left (Bernie Sanders) and right (every Republican) rather than do so indirectly through the proxy of Hillary Clinton. If the voters are persuaded to take the country in a different direction, then so be it. But it's strange to have his legacy held partially hostage to controversies over email server management and a 1994 crime bill he had nothing to do with.

The problem, of course, is that a third Obama term would be unconstitutional. The 22nd Amendment, ratified in 1951, prohibits presidents from serving more than two terms. But though it can't be repealed in time for the 2016 election, term limits clearly have to go. We should return to the democratic practice that served our country well for 150 years: Let the parties nominate whom they like, and let the voters choose their favorite.

The 22nd Amendment was a solution in search of a problem

Starting with George Washington, none of the first 30 men to become president served for more than two terms. But contrary to popular myth, this was not because all subsequent presidents followed some norm against three-termism. Ulysses Grant in 1880, Grover Cleveland in 1896, and Theodore Roosevelt in 1912 all sought third terms and all failed to obtain them for the more or less conventional reason that their political parties thought it would be wiser to head in a different direction.

When Franklin Roosevelt was successfully elected to third and fourth terms, Republicans, out of spite, sponsored a constitutional amendment to ban the practice.

But looking back, it is difficult to regret that FDR was in office from 1941 to 1945, a period of time during which his achievements included victory in the largest and most important war in all of history.

Would other possible leaders like white supremacist John Nance Garner, patronage machine politician James Farley, or political neophyte Wendell Willkie have done just as well? Maybe. But it's hard to argue that Roosevelt did a poor job in office or that there was anything problematic about him serving a third term.

Research says term limits are harmful

Serving as governor of a state isn't exactly the same as serving as president, but studying the impact of term limits on state politics can give us some insight into the promise and peril of third term presidents. James Alt, Ethan Bueno de Mesquita, and Shanna Rose did just such a study and found that second-term governors who are allowed to run for a third term do better than term-limited ones.

Compared with governors of limited-term states, reelection-eligible ones preside over states where "economic growth is higher and taxes, spending, and borrowing costs are lower."

They find that the same is true when you compare reelection-eligible veteran governors with first-term governors.

In other words, all else being equal, governors perform better when they are trying to win another term, and, all else being equal, governors perform better when they have more experience in office rather than less. The best governors are experienced governors who know what they are doing and who are trying to put that experience to use making citizens happy and winning another term.

This comports with the fact that our only multi-term president was one of our best presidents ever, and that several earlier presidents who sought third terms failed to obtain them. To run and win multiple times, you need to do a good job. And having people in office who are good at their jobs is good, not bad.

The case for term limits proves too much

Obviously, in a country without term limits sometimes a president will be reelected even though he is in fact a poor choice for office. Arguments against term limits tend to proceed by selecting specific historical circumstances in which it seems plausible that the electorate would have chosen poorly and then presenting them as knock-down arguments against third terms. But this style of argument proves far too much, and in fact functions as a generic case against democracy.

It's of course true that if you let the people decide who should lead them, they will sometimes choose poorly. But the reality is that we've never hit upon a better system, and arbitrarily constraining the choices to candidates with limited experience in office doesn't improve matters.

In his well-known article "The Arrogance of Power and the Case for Presidential Term Limits," Matthew Dickinson sets his sights on Roosevelt's fourth term, arguing that the president foolishly ran for and won a fourth term even though he should have known he was in very poor health.

But Roosevelt didn't do this alone. His colleagues in the Democratic Party were broadly aware of the situation, felt that continuity in office was important, and ditched the incumbent vice president in favor of a successor they considered acceptable. The system more or less worked.

Of course, a true blunder is possible. One could imagine Ronald Reagan securing election to a third term in 1988 and then beginning to suffer signs of mental impairment associated with Alzheimer's disease. In theory, if that had happened the president should have done the responsible thing and resigned, or else been forced from office by the Cabinet. In practice, it might not have worked out.

But in general there's no guarantee that voters won't make disastrous choices (George W. Bush won, after all), and dementia is a problem of aging, not of serving multiple terms in office. Bernie Sanders will be 75 in November, and the voters are allowed to reach their own conclusions about how much that worries them. Keeping Obama — who is 20 years younger than Sanders and 14 years younger than Clinton or Donald Trump — out of office in order to prevent dementia in the White House seems bizarre.

VIDEO: president Obama explains why he is so polarizing