Barack Obama. AP The wild, wacky exhibit that has been the Republican presidential primary — and the man who has become the party's standard-bearer — could be making more voters yearn for someone like the person currently sitting in the White House.

And that could be a big problem for the GOP.

Earlier this week, an NBC/Wall Street Journal poll found that President Barack Obama's approval rating had jumped to 51% — its highest point since his second inauguration.

NBC's team of political analysts called it the "most important number" out of the new poll.

"Why is it important? Because it means that Obama will be an asset to Hillary Clinton on the campaign trail unlike he was in the 2014 midterms, when his approval rating was in the low 40s," NBC's Chuck Todd, Mark Murray, and Carrie Dann wrote.

The 50% level might seem arbitrary. But historical precedent suggests it could bode well for Hillary Clinton, Obama's former secretary of state who is the Democratic frontrunner to succeed him.

Early this year, Obama's approval rating hit 50% in the weekly average from Gallup's daily survey. Two months later, his number in Gallup's poll stands at 52%. For Obama, whose approval ratings have been stuck in the mid- to low-40% range for much of his second term, it was a notable bump.

"While it's hard to pinpoint precisely why Obama's approval rating has risen among Democrats recently, there are a number of plausible explanations," wrote Andrew Dugan, a Gallup analyst, and Frank Newport, the organization's editor-in-chief, in a post earlier this year.

One of the explanations, the pair concurred, was that "the unusual status of the Republican primary race — exemplified in particular by frontrunner Donald Trump's campaign style and rhetoric — may serve to make Obama look statesmanlike in comparison."

Trump, who on Thursday secured enough delegates to clinch the Republican Party's presidential nomination, has come into Obama's crosshairs recently.

During a trip through Asia, Obama said Trump has "rattled" world leaders by being more interested in "tweets and headlines" than world affairs. Clinton's campaign has also turned its attention to the general election, beginning to paint Trump as a dangerous candidate unsuited for the unique challenges of the commander-in-chief position.

"President Obama, no matter the political stakes, has always spoken to Americans' aspirations and better angels," said Ben LaBolt, a former spokesman for Obama's 2008 and 2012 campaigns. "It's hard to argue that's what has driven the campaign narrative this year."

The president's approval ratings at this point are far better than his predecessor, President George W. Bush, off whose unpopularity Obama thrived during his 2008 run. His level is most directly comparable to former President Ronald Reagan, who in March 1988 held a 51% approval rating, according to Gallup.

That same year, voters selected George H.W. Bush — Reagan's vice president — to succeed him.

"Yes," said Ari Fleischer, President George W. Bush's press secretary, when asked earlier this year if Obama's apparent rising popularity poses a problem for the Republican Party.

"Certainly, going into an election spring and summer, it’s better to have an incumbent president increasingly popular rather than less popular if you’re the incumbent party," he told Business Insider.

The numbers present a striking contrast to some data points associated with the current Republican presidential frontrunner.

Barack Obama. AP Photo/Pablo Martinez Monsivais

Trump's favorability numbers are without precedent for a modern general-election candidate, according to the NBC/Wall Street Journal poll. Overall, 58% of voters viewed him unfavorably, according to the survey. And his net-favorability rating was negative 29 — only slightly better than two months before, when he garnered the worst net-favorability rating in the history of the NBC/WSJ poll for a major presidential candidate.

"I've been doing this [since] 1964, which is the Goldwater years," NBC/WSJ co-pollster Peter Hart told NBC of the relative unpopularity of many of the candidates earlier in the year. "To me, this is the low point. I've seen the disgust and the polarization. Never, never seen anything like this. They're not going up; they're going down."

However, Obama's approval rating at this point is actually lower than that of President Bill Clinton in March 2000. But, as Gallup has noted, the 2016 election is somewhat different than the one that featured George W. Bush running against Al Gore, Clinton's vice president.

Hillary Clinton is attaching herself to much of Obama's legacy. And Obama remains favorable to wide swaths of constituencies whom Clinton needs to turn out to vote in November. The president held high approval ratings among African-Americans (90%), Democrats (82%), Latinos (73%), and voters aged 18 to 34 (64%).

And despite the strong primary challenge from Sen. Bernie Sanders, in many ways, Clinton has run an incumbent-style campaign, and she has much of the party's establishment rallying behind her candidacy. That wasn't the case for Gore in 2000.

As Gallup's Dugan and Newport wrote earlier this year:

In comparison, the two most recent candidates running to succeed a two-term president of the same party — John McCain running to follow the unpopular Bush, and Al Gore trying to succeed the popular but scandal-prone Bill Clinton — went to greater pains to ensure they were not associated with the outgoing president.

They concluded: "Prior to that, George H.W. Bush in 1988 presented himself as a natural heir to the Reagan legacy and was able to win his own term."