Better late than never: Congressional leaders of both parties, fresh from their first-ever override of a President Obama veto, are already experiencing buyer’s remorse.

They now concede the president raised real concerns about the Justice Against Sponsors of Terrorism Act, which would let families of 9/11 victims sue Saudi Arabia. And, citing “unexpected ramifications” — like threats to Americans abroad — they want to change the law they’ve just forced through over his objections.

“Ramifications” like those we flagged Tuesday in asking Congress not to override.

All four of those now supporting amendments — Senate Majority Leader Mitch McConnell, House Speaker Paul Ryan, both Republicans, as well as House Democratic Leader Nancy Pelosi and Sen. Chuck Schumer — voted to override the veto.

It’s all well and good that they’re having second thoughts, but that should have happened a lot earlier. As White House spokesman Josh Earnest said: “What’s true in elementary school is true in the United States Congress: Ignorance is not an excuse.”