Democrats are demanding that Congress extend health care benefits, while Republicans are trying to wear them down with day after day of voting on a House-passed bill that would reopen the government temporarily, mostly at current spending levels.“Until they have eight or hopefully more — 10 or more — people who want to, decide they want to end the government shutdown, I’m not sure this goes anywhere,” Senate Majority Leader John Thune said Thursday. Although Republicans control the White House and both chambers of Congress, the Senate’s filibuster rules make it necessary for the government funding legislation to gain support from at least 60 of the 100 senators. That’s given Democrats a rare opportunity to use their 47 Senate seats to hold out in exchange for policy concessions.