Trump committed another impeachable offense last week -- and it had nothing to do with the Russia probe

With the barrage of headlines surrounding alleged ties between President Donald Trump and the Kremlin, it's easy to overlook the many other impeachable offenses he's racked up in his short presidential tenure.

One such offense, according to The Nation, occurred last week when the president continued his unilateral military offensive in Syria against pro-Assad forces without Congressional approval.

California's Democratic Rep. Ted Lieu (an Air Force veteran and Colonel with the Army Reserves) said in a tweet that Trump's actions are "frickin' illegal" because he has no Congressional authorization.

In a statement to The Nation, Lieu expounded on the illegality:

"For the second time in as many months, the US military has conducted airstrikes against pro-Assad forces in Syria," Lieu's statement read. "The Trump Administration does not have congressional authorization to carry out military strikes against the Assad regime."

Reps. Keith Ellison (D-MN), Raúl Grijalva (D-AZ), Mark Pocan (D-WI), who lead the Congressional Progressive Caucus, had similar sentiments to Lieu in a statement during last month.

"In the absence of an imminent threat to the United States, the president must seek Congressional authorization prior to any act of war. Trump failed to seek, much less gain, Congressional authorization," the statement read. "If President Trump believes that US military actions should be utilized against the Assad regime, he should immediately call the House and Senate back into session to debate and vote on the use of military force."

The continued use of force in Syria doesn't just upset Democrats -- GOP Rep. Justin Amash (R-MI) said in April that "atrocities in Syria cannot justify departure from Constitution, which vests in Congress power to commence war," and Republican firebrand Rand Paul (R-KY) invited the president to "come to Congress for a proper debate."

The president's continuance of military aggression in Syria without proper authorization from both houses of Congress constitutes yet another item on the growing list of impeachable offenses Trump has undertaken, but according to The Nation, impeachment "requires a level of respect for the Constitution that is rarely displayed by leaders of the House or the Senate".

Read Rep. Lieu's tweet about the president's Syrian airstrikes below.