With several polls this week showing that roughly two-thirds of Americans oppose Trump’s family separation policy and images of distraught children dominating television, many congressional Republicans were openly seeking a way out. But, by any reasonable standard, Capitol Hill Republicans marched themselves into this quagmire by either actively endorsing, or failing to effectively resist, almost every earlier step Trump has taken to redefine the party around his insular nationalism.

On trade, that became clear when traditionally free-trading congressional Republicans meekly acquiesced to Trump’s abandonment of the Trans-Pacific Partnership that created an American-led free trade zone across Asia. Complaints over Trump’s trade truculence from both elected Republicans and GOP interest groups (such as the leading farm lobbies) have grown louder recently as tensions have spiked with China, Europe, Canada, and Mexico; but even so, Senate Majority Leader Mitch McConnell has dismissively blocked bipartisan legislation to restrict the president’s authority to unilaterally launch trade wars.

On foreign policy, several Republican scholars lamented Trump’s open disdain for traditional U.S. allies on display at this month’s G-7 meeting and praise for North Korea’s oppressive leader Kim Jong Un. But not only did leading congressional Republicans bite their lips, so did the former secretaries of state and defense at the apex of the GOP foreign policy establishment.

The pull toward Trump has been greatest on immigration. Skepticism in the party during the 2016 primaries about his proposed restrictions on Muslim entry to the U.S. and his border wall have virtually evaporated—even the ostensibly more consensus House Republican immigration bill crafted by Speaker Paul Ryan would fully fund the wall.

Last June, all but seven House Republicans voted to withhold federal funding from “sanctuary” cities that fail to fully cooperate with federal immigration officials; not a single Senate Republican voted against that position in February. (The Ryan bill scheduled for a vote this week would provide private citizens a right to sue cities or states if their policies result in the release of undocumented immigrants who later commit a crime.) Reflecting the same movement, three-fourths of Senate Republicans voted in February for a Trump-favored plan that would have massively reduced legal immigration; many House Republicans are almost certain to vote this week for House Judiciary Committee Bob Goodlatte’s legislation that would impose comparable cuts.

With this pattern of deference from congressional Republicans, the Trump administration could be forgiven for assuming they would accept his “zero tolerance” immigration policy, which has led to hundreds of families being separated at the border. But of all the ways Trump has jettisoned the party’s internationalist traditions this proved the bridge, or cage, too far.