A powerful conservative group is trying to block efforts in the Senate to reinstate funding for ObamaCare in a must-pass government spending bill.

In a notice to senators Tuesday, the Club for Growth threatened to punish those who vote to end debate on the continuing resolution this week.

If successful, the procedural motion would pave the way for Senate Majority Leader Harry Reid (D-Nev.) to include ObamaCare funds in the spending bill over a conservative push to defund the law. 

{mosads}The Club warned Tuesday that any senator who supports the motion could be a target in future elections. The vote will be listed on the group’s congressional scorecard, an influential document that has inspired primary challenges against centrist Republican lawmakers.

“If [Reid] is successful, he will only need 50 votes to keep ObamaCare funding in the budget, and thus grow government and further erode economic liberty,” Andy Roth, the Club’s vice president of government affairs, wrote to senators.

The Club is one of several Tea Party-affiliated groups urging members to kill ObamaCare this week using the looming government shutdown as leverage. 

Another Tea Party-affiliated group, FreedomWorks, issued a similar notice to senators Tuesday afternoon.

The announcements are particularly sensitive because of the many Republican senators who oppose the defunding push or believe it is doomed to failure.

Senate Minority Leader Mitch McConnell (R-Ky.) notably said Monday that he would not seek to block debate alongside defunding champion Sen. Ted Cruz (R-Texas).

“Sen. McConnell supports the House Republicans’ bill and will not vote to block it, since it defunds ObamaCare and funds the government without increasing spending by a penny,” said a McConnell spokesman.

On a purely tactical level, Cruz, FreedomWorks and the Club are choosing a different path than Senate Republicans who have rallied around a plan to speed up the debate on the stopgap spending bill.

Those GOP lawmakers want the Senate to pass its version of the measure as soon as possible in order to give Speaker John Boehner (R-Ohio) time to make a counteroffer.

The current continuing resolution expires at the end of the month, and the government will shut down Oct. 1 unless Congress acts. 

—This post was updated at 4:15 p.m.