On May 31, Senator Mike Lee tweeted that he and 7 other Republican senators had signed a letter committing to:
1) not allow any increase to non-security related funding for the Biden administration, or any appropriations bill which funds partisan lawfare
2) not vote to confirm any Biden administration political or judicial appointees
3) not allow expedited consideration and passage of Democrat legislation or authorities that are not directly relevant to the safety of the American people

You can find the relevant tweet here: https://x.com/SenMikeLee/status/1796600766691672394

This market will resolve to "Yes" if a majority of Republican senators sign on to the mentioned statement by June 7, 2024, 11:59 PM ET. Otherwise, this market will resolve to "No".

In this case "a majority of Republican senators" means more sitting Republican senators have signed onto the mentioned statement than have not. At the present there are 49 Republican senators; if 24 Republican senators sign this letter, this market will not resolve to "Yes", however if 25 sign on, this market will resolve to "Yes". If the number of Republican senators changes within this time, a majority is still required (if three Republican senators becomes an independent so there are only 46 senate Republicans, 23 signees will not trigger a "Yes" resolution, but 24 will).

The primary resolution source for this market will be announcements made by relevant Republican senators, however a consensus of credible reporting will also be used.