(L/R) US Senator John Boozman, Republican from Arkansas, Senator Katie Britt, Republican from Alabama, and Senator Susan Collins, Republican from Maine, walk toward the Senate Chamber following a meeting with Senate Republicans at the US Capitol in Washington, DC, on June 4, 2026. President Donald Trump's agenda faces a series of tests in the US Senate on Thursday, as lawmakers began a marathon amendment process on a $70 billion immigration enforcement bill after weeks of Republican anxiety over some of his most contentious policy moves. (Photo by Kent NISHIMURA / AFP via Getty Images)