Sen. Bob Corker (R-Tenn.) said Wednesday that the U.S. military was poised to launch a “very targeted, very brief” operation against the Syrian government for using chemical weapons before President Obama called off the attack at the last minute.

{mosads}“I think the worst moment in U.S. foreign policy since I’ve been here, as far as signaling to the world where we were as a nation, was August a year ago when we had a 10-hour operation that was getting ready to take place in Syria but it didn’t happen,” Corker said at the 2014 Foreign Policy Initiative Forum in Washington.

Corker, ranking member of the Senate Foreign Relations Committee, also said “folks that were going to be a part of it with us” did not know about the president’s decision until “they watched the president on CNN.”

The remarks shed new insight on how far the military had planned for an attack, which the administration had readied to launch last August, after Syrian President Bashar Assad defied Obama’s “red line” against using chemical weapons against rebels in the country’s civil war.

Corker said after his onstage talk that his reference to the 10-hour operation was used to describe an operation that was going to be “very targeted, very brief, and hopefully have an impact.”

Obama had ordered the military to prepare for targeted strikes against Assad but changed his mind the evening before anticipated strikes, reportedly after consulting with adviser Denis McDonough, and decided to seek congressional approval first.

“Y’all have all read, it’s been widely chronicled, that there was an evening walk,” Corker said of the conversation with McDonough.

Critics say that decision weakened the U.S.’s credibility around the world and led to the U.S. striking a deal with Russian President Vladimir Putin to rid Syria of its chemical weapons.

“In essence — I’m sorry to be slightly rhetorical — we jumped in Putin’s lap, and we are where we are today in Syria,” he said.