Obama's approval rating up: Will that hurt the GOP?

President Obama's approval rating is the highest it has been in almost three years – and that's good news for Hillary Clinton and Bernie Sanders.

Some 50 percent of Americans approve of Mr. Obama’s job performance, according to a Gallup survey released Thursday.

That's 5 points higher than it was at the beginning of the year, and the uptick may be an unintended consequence of the bizarre Republican primary, marked by insults at entire demographic groups, nasty personal attacks, and the occasional anatomical reference.

"The unusual status of the Republican primary race..may serve to make Obama look statesmanlike in comparison," writes Gallup in its report.

That's good news for the eventual Democratic nominee, says Chris Ellis, a professor of political science at Bucknell University in Lewisburg, Penn.

"Even though Obama himself is not running for office, voters typically react by treating the nominee of the President's party as an extension of the President himself," he says. "So the fact that Obama is creeping above 50 percent in some polls ... suggests, among other things, that majorities of citizens are at least open to considering another Democrat. That's a big deal heading into a general election."

That's because presidential approval ratings have a clear effect on presidential elections, explains Natalie Davis, professor of political science at Birmingham-Southern College in Birmingham, Ala.

"All of the forecasting models say that presidential approval is one of two factors which predict who will win the presidency," she says. "The other most important factor is economic growth. Overall that bodes well for the Democratic candidate in November, although clearly, there is a long way to go before November 2016." 

In fact, a Rasmussen Reports analysis found a direct correlation between a president's approval rating and the fate of the incumbent party's nominee in the general election. Of the six open-seat elections since World War II, all three candidates seeking to succeed presidents with approval ratings below 50 percent were defeated, the two seeking to succeed presidents with approval ratings below 40 percent were decisively defeated, and two of the three candidates seeking to succeed presidents with approval ratings above 50 percent won the popular vote, according to an analysis by Alan Abramowitz, a professor of political science at Emory University.

"The fate of the incumbent party’s candidate is strongly influenced by the popularity of the outgoing president," writes Professor Abramowitz. "From that standpoint, the president’s rising approval rating in recent polls is good news for Hillary Clinton or whomever the Democratic Party eventually chooses as its nominee."

Notably, however, Obama's ratings have been among the most politically polarized of any modern president, a reflection of the political environment. Some 87 percent of Democrats approve of the job he's doing, compared to just 11 percent of Republicans, according to Gallup. 

That nearly 90 percent approval rating among Democrats is why both Sen. Sanders and especially Mrs. Clinton have sought to tie themselves to the President, says Carrie Skulley, assistant professor of political science at Albright College in Reading, Penn.

"Since Secretary Clinton has been more explicitly tying herself to President Obama and suggesting that her presidency would be an extension of his, we might expect higher approval ratings to help her more than Senator Sanders," she says.

But Clinton should be careful, cautions Tim Vercellotti, Professor of Political Science at Western New England University in Springfield, Mass.

"Should President Obama's numbers head south again in a significant way in the coming months, we can expect the Republican nominee to follow that strategy" of tying the Democratic nominee to an unpopular president, he says. "This would be especially true if Hillary Clinton is the Democratic nominee, because Clinton has worked hard to tie herself to the Obama administration on a number of policies, such as the Affordable Care Act."

There is historical precedent for this. Two recent presidential candidates have gone to great lengths to disassociate themselves from incumbent presidents: Republican John McCain running to follow the unpopular George W. Bush in 2008, and Democrat Al Gore trying to succeed the popular but scandal-prone Bill Clinton in 2000. Both were ultimately defeated.

But Obama's high approval ratings aren't necessarily bad news for Republicans, says Professor Ellis.

"Voters tend to be generally skeptical of giving a party three consecutive terms in office: after eight years, citizens are usually ready for a change and, all else equal, prefer the candidate of the other party," he explains. "Parties can obviously still win three terms in a row, but those running to succeed a two-term nominee generally pay a modest electoral penalty as a result of the public's general desire for change."

Still, Obama's approval ratings suggest that GOP attacks tying Clinton or Sanders to Obama may not be sticking, says Professor Davis.

"Virtually all the Republican candidates have claimed that to elect a Democrat would be tantamount to a third Obama term," she says. "It could be that that's what many voters want."

However much presidential approval ratings count, Obama's 50 percent ratings suggest the 2016 presidential election is likely to be very close, says Abramowitz.

Of course, as we've learned from Donald Trump's surprising staying power, Sanders's unexpected success, and electoral surprises on both sides, there's a whole lot more involved in determining who occupies the Oval Office, and a lot can happen between now and November.

[Editor's note: The original version of this story contained a misspelling of Professor Ellis's name.]