Around this time last year, U.S. President Barack Obama's secretary of state, John Kerry, was calling Syrian President Bashar al-Assad a "thug and murderer" after evidence indicated chemical weapons were used against his own people.

The way the White House was talking, it seemed airstrikes to punish Assad were inevitable, but then Obama diverted the final decision to Congress, saying he wouldn't act without approval. In the end, a  Russian proposal to get rid of Syria's chemical weapons resolved the debate about whether the U.S. should drop bombs on the wartorn country.

Now the airstrike debate is back, and the summer is once again wrapping up with Obama weighing his options on Syria. But this time, the target of the bombs wouldn't be Assad — it would be the Islamic State, the militant extremist group known as ISIS.

The administration won't officially confirm it, but senior officials have told reporters that Obama authorized surveillance flights over Syria to gather intelligence, which can be viewed as a precursor to airstrikes.

The U.S. has been conducting airstrikes against ISIS in Iraq for weeks now, and pressure has been mounting on Obama to expand the action into neighbouring Syria. If you really want to destroy ISIS, the argument goes, you can't stop at the Iraq border; you have to hit them where they are based — in Assad's territory.

Demands for a larger ISIS strategy grew louder last week after the group released a video of American journalist James Foley's beheading. He was kidnapped in Syria in 2012.

'Justice will be done,' Obama pledges

"Justice will be done," Obama vowed Tuesday during a speech in North Carolina. The U.S. will "do what's necessary" to go after those who harm Americans, he said, and will "take direct action where needed" to protect Americans at home and abroad.

If that means going into Syria, Obama is put in a somewhat awkward position. If he uses the U.S. military to root out ISIS in Syria, he could actually be doing Assad, the "thug and murderer" whom the U.S. wants out of power, a favour.

Experts in the area say Assad has allowed ISIS to flourish in his country because initially it was fighting the rebel groups that were trying to displace him. But more recently, ISIS has been turning its weapons on the regime, and now Assad is looking to contain the group that could threaten his power. His foreign minister said on Monday that Syria is ready for "co-operation and co-ordination" with the U.S. to fight the militants.

Obama's administration, however, is dismissing any notion that the U.S. and Syria are united in the same fight against ISIS.

James Foley parents John and Diane

Diane and John Foley devastated following word their son, American journalist James Foley, was killed recently by ISIS militants after he was kidnapped in Syria in 2012. Demands for a larger ISIS strategy by the U.S. grew louder last week after the group released a video of Foley's beheading. (Jim Cole/Associated Press)

"It is not the case that the enemy of my enemy is my friend," Benjamin Rhodes, Obama's deputy national security adviser, said in the New York Times on Tuesday.

While not confirming any intention to go into Syria, the White House has signalled it won't work with Assad or seek his permission if it does proceed with airstrikes.

It's not a surprise that Assad is seeking co-operation with the U.S. to fight ISIS, said Paul Salem, vice-president of policy and research at the Middle East Institute.

"The Assad regime wants to use this as an opportunity to rebuild its relations and legitimacy with the West which it lost three years ago," he said in an interview. "They would like that because it would legitimize them — and the U.S. is not going to go there politically."

U.S., Syria not on same page

The U.S. might give a heads-up to Syria about where and when airstrikes would be carried out so that its planes aren't shot down by Assad's forces, but that would likely be the extent of any co-ordination, Salem said.

Assad will try to portray the U.S. and Syria as being on the same side of a fight against ISIS, but it's simply not the case, Salem and others say.

SYRIA-ASSAD/AMNESTY

A man holds a roll of pictures of Syrian President Bashar al-Assad during a rally in Damascus in 2011. Assad's regime could benefit if the U.S. decides to launch airstrikes against the militant group ISIS in Syria. (Khaled al-Hariri/Reuters)

"To say that the U.S. and the Assad regime are on the same page with ISIS — only on the surface. In effect, they are not," Salem said.

Elliott Abrams, a senior fellow at the Council on Foreign Relations, holds the same view.

"Some days [Assad] fights them and other days he gives them a free pass because he would like them to take on the Syrian rebels. To view him as an ally in the fight against ISIS is, I think, wrong. He's been playing both sides," Abrams said.

'What has changed is ISIS"

Obama was calling a year ago for Assad to go, and that hasn't changed.

 "What has changed is ISIS," said Abrams.

Some of the arguments for not bombing Syria last year included concerns over the capabilities of its Russian-supplied air defence system and over the skills of the opposition rebels.

"All of this has been swept away by the growing power of ISIS," said Abrams. The calculations have changed and you now have senior officials calling ISIS a serious threat to U.S. interests.

But there is a key difference for the U.S. when it comes to targeting ISIS in Iraq and targeting them in Syria.

The U.S. says it is conducting the airstrikes in Iraq at the invitation of the Iraqi government, and on top of that, there is an Iraqi army and a Kurdish force in the North for the U.S. to arm and assist.

In Syria, Assad is an enemy who won't give the U.S. free reign in conducting military operations there, and the U.S. of course doesn't want to provide assistance to his forces to ward off ISIS.

Obama has long resisted getting drawn into the Syrian conflict and didn't want to get involved in Iraq again either, but ISIS has forced the U.S. to revisit its policies in the region.

"If there are any airstrikes in Syria, that would be another very significant change in American policy," said Abrams.

It's a change that Obama will have to handle delicately given his past resistance and the fact that Assad, whom he has called a ruthless leader that needs to step aside, isn't going anywhere and could stand to benefit from the U.S. action.