It’s easy to vote to constrain the executive branch’s power when the Office Oval is held by a member of the opposite party. It's harder when it involves voting against your own party.

So yes, the 47 Senate Democrats who voted Thursday to pass a war powers resolution restricting President Trump’s ability to wage war against Iran without the constitutionally required congressional approval do deserve credit (although it’s worth noting how many of them weren’t willing to do the same with former President Barack Obama and Libya). But it’s really the eight Senate Republicans who broke with their party in the Thursday vote and helped pass the resolution who deserve the most praise.

Led by outspoken constitutional conservatives Sens. Rand Paul and Mike Lee, other Republicans who voted for the resolution include Sens. Lamar Alexander, Jerry Moran, Susan Collins, Todd Young, Lisa Murkowski, and Bill Cassidy. Paul described the vote as “a fundamental constitutional debate” that is “bigger than any one senator, bigger than any one president, bigger than any political party.” Lee added that limiting the president’s ability to wage unconstitutional war “doesn’t show weakness. ... That shows strength.”

They’re both spot on. Voting for the war powers resolution isn’t about being pro-Trump or anti-Trump or being Republican versus Democrat. It’s a vote for upholding the Constitution and the limits it wisely imposes on the executive branch.

The resolution “directs the President to terminate the use of United States Armed Forces for hostilities against the Islamic Republic of Iran or any part of its government or military, unless explicitly authorized by a declaration of war or specific authorization for use of military force against Iran.” The enforcement of these kinds of guardrails is long overdue.

After all, the Constitution is quite clear : “The Congress shall have power to … declare war.” Yes, as commander in chief, the president does have the lawful power to respond to imminent attacks or take protective action. But the executive is simply not supposed to be able to start wars or engage in protracted military offensives on his own without proper congressional authorization. Sadly, illegal wars have become the status quo: Take, for instance, Obama launching a military intervention into Libya without authorization. (Guess how that worked out? Libya is now a failed state.)

Those Republicans reasserting this right with respect to Iran are doing the right thing, even though the conflict fortunately seems to have de-escalated on its own.

As Washington Examiner contributor Daniel DePetris wrote , it’s important that Congress have this responsibility and be forced to debate military action rather than a president being able to launch conflict at will because “only a national discussion about military force can serve as a guardrail to hasty, reckless interventions that create more problems than they solve and saddle our country with more endless, expensive, and purposeless foreign commitments.”

Sadly, some hyperpartisan critics will almost certainly blast Paul, Lee, and the other Republicans for their supposedly insufficient loyalty to Trump and the Republican Party after this vote. But senators do not swear an oath to Trump or the Grand Old Party. They swear their oath to the Constitution and the people of this country.

Trump has promised a veto. But still, kudos to these eight Republicans for fulfilling their oath this week in the face of enormous pressure.