Alumni from the previous two administrations sparred Tuesday evening over who deserves credit for U.S.-backed Syrian forces retaking the city of Raqqa from the Islamic State in Iraq and Syria: President Trump or former President Barack Obama Barack Hussein ObamaDemocratic Senate campaign arm outraises GOP by M in August A federal court may have declared immigration arrests unconstitutional Blunt says vote on Trump court nominee different than 2016 because White House, Senate in 'political agreement' MORE.

"I think it took the whole world by surprise how quickly they were able to take territory in Iraq and Syria back when they first really rose to prominence," former Obama State Department spokeswoman Marie Harf told host Martha MacCallum on “The Story” on Tuesday night.

"After our administration got a better sense of what was going on, we did put in place a plan that we see being carried out now," she continued. "The plan to retake Raqqa was put in place during the Obama administration.

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"President Trump has done something — he has made some tweaks around the edges, but this is the plan that the military has had in place for a long time time.”

Karl Rove, a former senior adviser and deputy chief of staff to President George W. Bush, pushed back on Harf's perspective, saying Trump's decision to listen to his generals played a big role in ISIS’s Raqqa fall.

"President Trump did two things," Rove said. "First of all, he made clear that we are going to take action, and we saw that, unlike what President Obama said, that’s a red line that they dropped gas on their own people."

“When the Syrians dropped gas on their own people under this president he immediately took action, and then he listened to the military and unleashed them on the mission they could do, which is setting up a force of Syrians to work with American trainers and American assistance to do what we saw today," he added.

"Let’s not kid ourselves, the battle against ISIS is going to continue. They’ve been kicked out of Raqqa, but just like al Qaeda, we will face these people for years to come."

Rove has served as a Fox News political analyst since 2008. Harf joined the network in January.

The Syrian Democratic Forces (SDF) declared on Tuesday that Raqqa, the last of ISIS's major strongholds, had been taken back from the terror group.

The SDF is a U.S.-backed mix of Kurdish and Arab fighters who have been engaging ISIS in its de facto capital for more than four months.