Follow the money
On Thursday, Sen. Lindsey Graham (R-S.C.) said that the "financial contributions will stop" if the GOP does not pass tax reform. The senator's blunt prediction was reported by NBC News producer Frank Thorp V and later retweeted by Graham himself:
Graham is not first the GOP congressman to admit that the party's financial contributions are somewhat reliant on the passage of a tax bill; earlier this week, Rep. Chris Collins (R-N.Y.) told a reporter, "My donors are basically saying, 'Get it done or don't ever call me again.'" Politico reported in early October that many GOP donors were frustrated by Congress' inaction and that donations to the Republican Party had stalled after their repeated failures to repeal ObamaCare.
Last month, Graham predicted also that the Republican Party would lose control of Congress if they did not pass tax reform. He echoed that sentiment Thursday, saying Republican incumbents would likely lose in primary challenges in 2018 if the tax effort failed.
President Trump has previously said that he wants to sign a tax reform bill by Christmas, though he has repeatedly and falsely claimed that the proposed tax plan would be "the biggest tax cut in the history of our country."