After Senate Majority Leader Mitch McConnell (R-Ky.) delayed until Thursday afternoon the second procedural vote on a bill that would punish boycotts of Israel, Palestinian rights groups that have condemned the legislation as “unconstitutional” kept up urgent calls for Americans to pressure their senators to block the measure again.

“You still have time to contact your Senators to again defeat this unconstitutional bill that encourages states to punish people for boycotting for Palestinian rights,” declared Josh Ruebner, policy director at the U.S. Campaign for Palestinian Rights.

The procedural vote on the legislation—S.1—is expected to come as early as 1:45 pm ET on Thursday.