The Washington Post reports that, although President Donald Trump and his staff were hesitant to campaign in Alabama for establishment-friendly Luther Strange, Swamp Republicans forced the president’s hand — fearing that a victory for Judge Roy Moore would motivate several allies to retire from the Senate rather than face Breitbart-backed challengers in 2018.

From the Washington Post:

White House Chief of Staff John F. Kelly, who has tried to control what information Trump receives about the Alabama race, was initially wary of the president appearing with a senator who might lose. He preferred Trump spend his time on policy initiatives such as tax reform rather than rousing crowds at political rallies. Likewise, Bill Stepien, the White House political director, urged caution and at first recommended that Trump stay out of the state, administration officials said.

Senate Republicans, however, were unwilling to let the president turn his attention elsewhere. A Strange defeat, they worried, could prompt some GOP senators to retire to avoid facing the wrath of anti-establishment voters and the likes of Bannon’s Breitbart News.

Kelly, who came around to backing the rally, was also told by several senators that Republicans might be hesitant to fully back Trump’s agenda if they were uncertain about his support for them.