Concerning the Ryan-Murray budget compromise, the next milestone is a cloture vote currently scheduled for Tuesday. Senate Democrats have 55 votes. They need 60 votes for cloture to cut off debate, meaning they'll need at least 5 GOP Senators to vote with them to stop the filibuster.
If Democrats can get 60 votes for cloture, debate ends and the Ryan-Murray budget passes on a simple majority vote, likely with very few GOP Senators voting for it. If not, the status quo is maintained and additional sequester cuts take effect in January.
Several GOP Senators face primary challenges by Tea Party-backed candidates who allege the incumbents are insufficiently opposed to big government spending and deficits. Senators with primary challengers are hesitant to support the budget deal. Ironically, Senate Minority Leader Mitch McConnell is one of these.