Failed presidential candidate Sen. John McCain (R-AZ) blamed President Donald Trump for the most recent chemical weapons attack in Syria.

“President Trump last week signaled to the world that the United States would prematurely withdraw from Syria,” McCain wrote in a statement, saying that Syrian dictator Bashar al-Assad was “emboldened by American inaction.”

The Arizona senator urged Trump to launch a military strike against Syria in response to the use of chemical weapons, citing his decision to bomb an airbase in Syria in 2017.

“The President responded decisively when Assad used chemical weapons last year. He should do so again, and demonstrate that Assad will pay a price for his war crimes,” he wrote.

The senator tacitly endorsed Trump’s specific condemnation of Russian President Vladimir Putin’s decision to back Assad but demanded specific action.

“President Trump was quick to call out Assad today, along with the Russian and Iranian governments, on Twitter,” McCain wrote. “The question now is whether he will do anything about it.”

McCain acknowledged that former President Barack Obama’s inaction was also to blame for the ongoing mess in Syria, pointing out that “history will render a bitter judgment” on his administration.

“We can and should change course – starting with a comprehensive strategy that lays out clear objectives for our mission there,” he wrote. “It’s not too late to stop Assad’s impunity and begin to rewrite this terrible chapter in our history.”