House Committee on Oversight and Government Reform members, Rep. Tom Massie, R-Ky., left, and Ron DeSantis, R-Fla. talk on Capitol Hill in Washington, Wednesday, June 15, 2016. (AP Photo/Lauren Victoria Burke)

Sen. Marco Rubio called on Wednesday any denial of Syrian President Bashar Al-Assad’s responsibility for a chemical attack in his own country “grotesque” and “fake news at the highest.”

But one Republican House colleague does not agree. Kentucky Rep. Thomas Massie, in an interview on Wednesday morning, said he could not be certain that Assad was responsible for the attack that killed scores of civilians — including children. The United States has blamed Assad’s government.

“Frankly, I don’t think Assad would have done that – it does not serve his interests, it would serve to draw us into that civil war even further,” Rep. Thomas Massie (R-Ky.) said on CNN. “It’s hard for me to understand why he would do that if he did.”

Interviewed on Capitol Hill following that statement, Massie didn’t back down.

“Do you have the facts?” he challenged a reporter.

“Let me ask you this: Who benefits? Who benefits, if chemical weapons were used and America weighs in on the side of the rebels, or wades into a war against Assad?” Massie answered. “How does Assad benefit from that?”

When asked if he believed the latest attack would compel the United States to take a more active role in Syria’s war, Massie demurred, noting that any potential involvement in a war “better come to a vote here, in the House of Representatives” and that he hoped Trump would exercise the “restraint in foreign policy” he campaigned on.

Massie could be increasingly a party of one on this issue. Trump said Wednesday that the images from the attack in Khan Sheikoun of “innocent children, innocent babies – babies, little babies – with a chemical gas that is so lethal…that crosses many, many lines, beyond a red line.”

Secretary of State Rex Tillerson went even further, telling reporters Wednesday that “there’s no doubt in our mind that the Syrian regime under the leadership of Bashar al-Assad is responsible for this horrific attack.” He added that “we think it’s time that the Russians really need to think carefully about their continued support of the Assad regime.”

Trump’s comments about the Syria attack come one day after he blamed former president Barack Obama’s “weakness and irresolution” for emboldening Assad, particularly when Obama said that the use of chemical weapons would be a “red line” – but then did not act forcefully after Assad used chemical weapons.

Massie, a libertarian who came to Congress in 2012, is known for being a contrarian in Congress, and often butting heads with his colleagues.

Yet when it comes to Syria, Massie’s understanding of his colleagues’ readiness to go to war – and any concerns Assad might have about such a potential invasion – are somewhat belied by what action his colleagues have thus far called for in the wake of the latest attack.

In Congress, lawmakers calling for a stronger response to the chemical gas attack also stopped short of committing American soldiers to a war.

Sen. Ben Cardin (D-Md.), appearing with Rubio, called on Wednesday for additional sanctions against the Assad regime and anyone who supports it such as Russia and Iran.

They senators called for a “clear U.S. policy that President Assad has no legitimacy as the leader of Syria,” and finding some way – such as a special international tribunal – to make sure Assad is “held accountable for these war crimes,” along with Russian President Vladimir Putin, for supporting him.

In an indirect challenge of Massie’s logic that Assad had nothing to gain from carrying out a chemical attack on his own citizens, Rubio indirectly criticized the Trump administration for indicating it would no longer seek to depose Assad.

Just last week, Secretary of State Rex Tillerson and Ambassador to the United Nations Nikki Haley said publicly that removing Assad is no longer a U.S. priority — breaking with Western allies.

“If you’re Bashar al Assad and they’re basically sending you a signal that in the end, they just want you to finish this war quickly…that is, in my view, something that would encourage him to do something like what we’ve just seen,” Rubio said. “So I personally do not believe it’s coincidental.”

Historians and activists have pointed to a long history of Assad regimes taking extreme measures against their own people, from the infamous 1982 massacre in which Assad’s father and predecessor, Hafez al-Assad, killed thousands in an effort to crush an uprising in Hama, to attacks in the ongoing war, such as the 2013 chemical attack in Ghouta, a rebel-held suburb of Damascus.

Karen DeYoung contributed to this report.