It was just eight months ago, after the midterm elections gave Republicans control of both the U.S. House and the Senate, that the punditry began dismissing Barack Obama as a lame-duck president.

What a difference a week can make. 

In a span of seven days, the U.S. Supreme Court handed Obama two key victories. (One codified Obamacare, his signature piece of domestic legislation, while the other legalized same-sex marriage across the nation, an issue that, as president, he had slowly but surely come to support and embrace.)

Meanwhile, the Republican-controlled Congress gave him "fast track" negotiating authority on the big Pacific Rim trade deal he had been championing, and this week he announced the U.S. and Cuba would reopen their embassies in Havana and Washington, another step in his policy to re-start diplomatic relations with old enemies.

All this, while U.S. and Iranians officials were trying to hammer out some kind of lasting agreement on Iran's controversial nuclear program, a deal that, other failures aside, could cement a foreign policy legacy. 

Obama, of course, still has a year and a half before he leaves office, and even then, it can be years or decades before the true legacy of a U.S. president is known. 

But for the first time in over two years, the president's approval rating bumped up five points to the 50 per cent mark, according to a CNN poll last week.

It's an ironic number, for sure. But with Americans celebrating Independence Day weekend, Obama's sudden burst of popularity and achievements has U.S. pundits and historians talking about the L-word.

Not in top 10

As for legacy, "it's too soon to tell in part because we don't know what the impacts will be of a lot of the policies he put into place," said Brandon Rottinghaus, associate professor of political science at the University of Houston. "His signature is health-care reform and the effect of that on U.S. health-care system has yet to be completely determined. That will have to be sorted."

But Rottinghaus said there are some measures on which Obama can be  judged. In fact he and his colleague, political scientist Justin Vaughn, administered a survey last year of 162 members of the American Political Science Association's presidents and executive politics section, asking  them to rate the U.S. presidents. 

Charleston Shooting

The culmination of Obama's week came in a moving eulogy he delivered for Rev. Clementa Pinckney, one of the victims of the Charleston church shooting. (David Goldman/Associated Press)

At the time, Obama ranked 18th, just below George H. W. Bush.

"There are some successes you can point to. Some question marks you can point to."

Rottinghaus said Obama deserves praise for stabilizing the fragile economy he inherited following the 2008 financial meltdown, for keeping the country out of any serious military conflict and, basically, for maintaining a status quo in foreign policy.

But questions still remain over what will result from the negotiations with Iran. 

"You get to be in the top 10 in these sorts of rankings if you win a war or oversee tremendous economic success. He's done half of both of those things," Rottinghaus said.

Had an impact

Alvin Felzenberg, U.S. presidential historian and author of The Leaders We Deserved and a Few We Didn't: Rethinking the Presidential Rating Game, said Obama's legacy so far is a mixed bag — high grades in some areas and low grades in others.

Top 10  U.S Presidents

1. Abraham Lincoln
2. George Washington
3. Franklin Delano Roosevelt
4. Theodore Roosevelt
5. Thomas Jefferson
6. Harry S. Truman
7. Dwight Eisenhower
8. Bill Clinton
9. Andrew Jackson
10. Woodrow Wilson  
 

Source: Survey by the American Political Science Association

"There's no question he's had an impact," Felzenberg said.

While he said the jury is still out on Obamacare, as a piece of legislation, it will rank up there with social security and medicare in terms of its social and political impact.

"On character, on symbolism ... I think his personal grace and I think his own story, his eloquence and his lack of character defects, with the exception of self absorption, make him an extremely powerful president who we will remember." 

He also said Obama deserves credit for putting forth a vision for the country. And while he gets marks for taking out Osama bin Laden and continuing George W. Bush's drone attacks against al-Qaeda targets, his foreign policy has been mostly a bust, he said.

The Arab Spring has been a disaster, Libya is a failed state and historians will question whether it was Obama or George W. Bush who left Iraq worse off than it was before, Felzenberg said.

He also noted Obama has done nothing to check the power of Russian President Vladimir Putin, and continues to put up straw man arguments that the only alternative to dealing with people like Putin is to go to war.

As for the economy, Obama has overseen one of the weakest recoveries in recent history, Felzenberg said. And the rollout of Obamacare, along with the scandals in the Veterans Health Administration, the handling of the U.S. embassy attack in Benghazi, Libya, and even the email scandal now facing Hillary Clinton all raise questions about his competency. 

Obama-Tan Suit

Obama himself may have set the bar on how he should be measured, suggesting early on he hoped to be a transformative figure, much like former Republican president Ronald Reagan. (Scott Stewart/Associated Press)

Felzenberg said Obama certainly doesn't rank up there with the greatest presidents, such as Abraham Lincoln or George Washington, nor is he in the top 10, which would include Harry Truman, Franklin Roosevelt and Ronald Reagan. 

But he said he would place him at the higher end of "the average group," amongst former presidents like Bush Sr. and Bill Clinton. 

Set the bar too high?

Obama himself may have set the bar on how he should be measured, suggesting early on he hoped to be a transformative figure, much like former Republican president Ronald Reagan.

Neither Felzenberg or Rottinghaus believe Obama has accomplished that, but U.S. presidential historian Richard Norton Smithsays it may be too soon to really judge. 

The country took a rightward shift during Reagan's presidency that extended even into the Clinton years, Smith said.

"Essentially, under Barack Obama, there is a distinct shift to the left, certainly in the nation's cultural consensus. Whether this was an accident in timing, who knows."

Smith said the more controversial, the more embattled and ambitious the president is, the longer it takes for history to size him up. 

"We don't know yet if he's a transformative president. We know that he's a consequential president," Smith said.

"He may very well have contributed to cultural and political transformative action."

With files from The Associated Press