President Trump has increasingly moved the national conversation toward immigration by working to send National Guard troops to border states, setting up a conundrum for congressional Republicans who were hoping to run on the tax cuts they successfully passed this year.

Trump’s renewed immigration push could move vulnerable GOP lawmakers off the script that Republican groups have already spent millions of dollars writing through ad campaigns touting the benefits of tax reform. And it could put centrist Republicans in a difficult position if Trump demands his party revisit controversial restrictions on legal immigration while its members are trying to hold onto suburban districts that contain energized Democratic constituents.