Why could they pass anything up until 3 weeks ago? I though filibustering meant the senate always needed 60 votes if the opposing party wants to block the legislation.
They could have used the budget reconciliation process to bypass the filibuster. Instead they used their one opportunity this year to do that to get the tax bill passed. If they hadn't insisted on forcing through a (historically unpopular) tax bill, they could have passed a funding bill over any Democratic opposition.