WASHINGTON—Leading lawmakers on Thursday said they were working on ways to mitigate possible unintended consequences of legislation letting Americans sue foreign governments over terrorist attacks, just one day after both the House and Senate soundly overrode President Barack Obama’s veto of the bill.
Some lawmakers expressed buyer’s remorse on the legislation, which would enable victims of the Sept. 11, 2001, terror attacks and their families to sue Saudi Arabia, worrying that the bill could spark reciprocal lawsuits and put Americans abroad in the legal crosshairs of foreign governments.
“It appears as if there may be some unintended ramifications,” Senate Majority Leader Mitch McConnell (R., Ky.) told reporters Thursday. “I do think it’s worth further discussing.”
The president vetoed the bill last Friday, arguing that it did little to deter future terrorist attacks and could endanger U.S. intelligence officials and diplomats abroad by eroding sovereign immunity, the centuries-old legal doctrine that generally protects national governments, including the U.S., from being sued against their will. Mr. Obama said Wednesday night that Congress had made a “mistake” in overriding his veto for the first time in his presidency.
The bill specifically would establish an exception to U.S. laws barring lawsuits against foreign governments, allowing court action by victims of terrorist attacks on U.S. soil.
Lawmakers said Thursday that they would seek to tighten the bill when they return to Washington after the November elections in an effort to limit its repercussions.
House Speaker Paul Ryan (R., Wis.) said Thursday he hoped to find some way to “protect our service members overseas from any kind of legal ensnarements or retribution” while still allowing Sept. 11 victims and their families to go to court.
“There will be an attempt to narrow the effect of what we’ve done,” Senate Foreign Relations Committee Chairman Bob Corker (R., Tenn.) told reporters.
Lawmakers are looking at options including limiting the bill’s scope just to the Sept. 11 attacks, changing some of the technical definitions or thresholds in the bill and establishing a tribunal of experts who “could first determine if there was culpability there,” Mr. Corker said.
Sen. Charles Schumer (D., N.Y.), one of the bill’s main sponsors, along with Sen. John Cornyn (R., Texas), dismissed the idea of narrowing the legislation’s scope to just the Sept. 11 attacks.
“That tells the Saudis, ‘go ahead and do it again and we won’t punish you,’” Mr. Schumer said Thursday. While he said he was willing to look at any proposal, Mr. Schumer said it would have to be “something that doesn’t weaken the bill and limit the right of these families to get their day in court and justice” to secure his approval.
But Mr. Corker said he thought Mr. Schumer would be up against a broad, bipartisan effort to take steps to hem in the legislation.
“There’s a large number of people here who would like to see the bill narrowed,” Mr. Corker said. On Wednesday, Mr. Corker and his committee’s top Democrat, Sen. Ben Cardin of Maryland, circulated a letter signed by 28 senators calling for taking action to head off any unintended consequences.
Saudi Arabia, which strongly opposed the bill, has denied any role in the Sept. 11 attacks and U.S. officials have backed that position.
“It is our hope that wisdom will prevail and that Congress will take the necessary steps to correct this legislation in order to avoid the serious unintended consequences that may ensue,” Saudi Arabia’s Ministry of Foreign Affairs said in a statement Thursday evening.
Republicans said Thursday the White House should have done more to alert them earlier in the process of the bill’s possible consequences.
“That was a good example, it seems to me, of failure to communicate early about the potential consequences of a piece of legislation that was obviously very popular,” Mr. McConnell said Thursday. “I told the president the other day that this is an example of an issue we should have talked about much earlier.”
White House press secretary Josh Earnest said by trying to shift blame to Mr. Obama’s outreach effort on the bill lawmakers are showing a case of “rapid onset buyer’s remorse” over the “terrible mess that they have made.”
Mr. Earnest said it is hard to take seriously the suggestion that lawmakers didn’t know the ramifications of the bill, given the volume of letters sent to them outlining the consequences from a host of senior administration officials, including Mr. Obama and Central Intelligence Agency Director John Brennan, as well as former national security officials and business leaders. He said Mr. Obama has been making the case for months about why the bill would be damaging.
If lawmakers weren’t aware of the consequences before voting, he said, “Ignorance is not an excuse, particularly when it comes to our national security.”
Mr. Earnest called Wednesday’s vote an “abject embarrassment” and said “it’s awfully late” to try to reverse it, but that the White House is open to hearing their proposals.
“If there are members of Congress who’ve had a change of heart…we would welcome action to solve the problem they created,” he said.
Write to Kristina Peterson at kristina.peterson@wsj.com and Carol E. Lee at carol.lee@wsj.com