Kentucky Sen. Rand Paul is taking a swipe at fellow Republican senator John McCain for traveling to Syria last year to meet with Syrian rebels.

Paul didn’t specifically mention McCain’s name in his Wall Street Journal op-ed, “How U.S. Interventionists Abetted the Rise of ISIS,” published in Thursday’s paper. But it’s clear who Paul is talking about when he criticizes those who “traveled to Syria from America to give moral and material support to these rebels even though there had been multiple reports some were allied with al Qaeda.”

McCain in 2013 famously traveled to Syria, posting a photo to his Twitter account of his travels.

Important visit with brave fighters in #Syria who are risking their lives for freedom and need our help pic.twitter.com/tx4uX572ZP — John McCain (@SenJohnMcCain) May 28, 2013

Paul and McCain have long sparred over foreign policy. In his op-ed, Paul criticizes the “hawkish members of my own party” like McCain who advocated military action against Syria last year.

“Some said it would be ‘catastrophic’ if we failed to strike Syria,” Paul wrote. “What they were advocating for then—striking down Assad’s regime—would have made our current situation even worse, as it would have eliminated the only regional counterweight to the ISIS threat,” Paul said.

It was McCain who used the word “catastrophic” last year when advocating for strikes.

Paul also takes aim at President Obama and former Secretary of State Hillary Clinton in the op-ed, provoking the Democratic National Committee to release a statement rebutting Paul and branding him an isolationist.

“It’s disappointing that Rand Paul, as a senator and a potential presidential candidate, blames America for all the problems in the world, while offering reckless ideas that would only alienate us from the global community,” DNC national press secretary Michael Czin said.

Added Czin: “That type of ‘blame America’ rhetoric may win Paul accolades at a conference of isolationists but it does nothing to improve our standing in the world. In fact, Paul’s proposals would make America less safe and less secure.”

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