"(Syrian President) Bashar Assad and his friends, the Russians, take note of what Americans say," the Arizona Republican told CNN's Alisyn Camerota on "New Day." "I'm sure they took note of what our Secretary of State (Rex Tillerson) said just the other day that the Syrian people would be determining their own future themselves -- one of the more incredible statements I've ever heard."
"I'm sure they are encouraged to know the United States is withdrawing and seeking a new arrangement with the Russians," he added. "It is another disgraceful chapter in American history and it was predictable."
The Trump administration doubled down last week on prioritizing the fight against ISIS over ending the Syrian civil war and getting rid of Assad, the policy under the Obama administration.
Activist groups blamed Assad's regime for a Tuesday attack
where dozens of people, including at least 10 children, were killed and more than 200 were injured as a result of asphyxiation caused by exposure to an unknown gas or chemical agent in northern Syria.
McCain -- a vocal critic of President Donald Trump's foreign policy
-- said the commander in chief needs to speak out against Assad and promise that his allies will pay a price for their actions against the Syrian people.
"I want to hear him say we're going to arm the free Syrian army," he said. "We're going to dedicate ourselves to the removal of Bashar al-Assad. We're going to have the Russians pay a price for their engagement. All players here are going to have to pay a penalty and the United States of America is going to be on the side of people who fight for freedom."
But McCain said he sees no clear foreign policy doctrine coming from the current administration.
"I don't see any doctrine right now. I do have great confidence in the security team around the President," he said. "I hope they will develop a strategy, stand up and give the President the advice and counsel I believe he needs and could get from that team."
McCain didn't limit his criticism to Trump but compared the President's lack of action to that of the Obama administration, saying neither president took the situation seriously enough.
"We've seen this movie before, when Barack Obama said they would have a red line and they crossed it and he did nothing," McCain added.
McCain wasn't the only Republican encouraging the US to respond more forcefully. Sen. John Kennedy said the US can't just sit back and not respond to Assad.
"It is probably the case that Assad is testing President Trump and he's testing our new Secretary of State Tillerson," the Louisiana Republican told CNN's Chris Cuomo. "We'll have an appropriate response now. Of course, what's appropriate will be much debated, but we can't just do nothing."
"We can't let them cross this line without having consequences," he added.