Scandals have typically operated as a cloud over a president’s agenda. But the Russia-related legal challenges swirling around President Trump are functioning more like a cloak for his joint agenda with congressional Republicans. That difference captures the GOP’s decision to govern in a manner aimed almost entirely at stoking their hard-core base—a critical calculation that could determine their fate in the 2018 election, and possibly the 2020 contest, as well.

In the week since fired FBI Director James Comey leveled his explosive charges at the president, Capitol Hill Republicans have followed a two-track response. With virtual unanimity, they have insisted that even if Trump did everything Comey alleged, the behavior does not warrant criminal action or impeachment. And simultaneously, while the Trump-Comey confrontation has monopolized media attention, both chambers have advanced deeply conservative policy proposals—with House Republicans voting to repeal the major financial regulations approved under former President Barack Obama, and Senate Republicans working in private toward a plan to repeal Obama’s Affordable Care Act.

Both of these responses rest on the calculation that Republicans can best avoid losses in 2018 by mobilizing their base supporters, no matter how other voters respond to their actions. But the choice to aim their governing decisions at such a narrow spectrum of Americans could magnify the risks facing Republicans in 2018—and, for that matter, Trump in 2020. As Trump’s presidency careens through increasingly turbulent waters, congressional Republicans are lashing themselves ever more tightly to its mast.

That was most apparent in their collective shrug at Comey’s Senate Intelligence Committee testimony. Strikingly, no leading Republican argued that Comey was fabricating when he said Trump encouraged him to drop the FBI investigation into former National Security Adviser Michael Flynn. Rather, in virtual unison, Republicans declared that even if Trump made the remarks Comey reported, his actions were at most inappropriate, and not illegal.

The unanimity among Hill Republicans contrasted sharply with the response to Comey’s testimony from the mainstream legal community. Some experts defended Trump’s actions. But a wide array of former federal prosecutors, like prominent former U.S. Attorney Preet Bharara; Watergate investigators; and law professors argued that the pattern of behavior Comey described justified opening an obstruction-of-justice investigation. Congressional Republicans have summarily dismissed those conclusions.

That supine acceptance follows the pattern established when Trump previously violated other norms, like not releasing his tax returns. Every time Trump has broken a window, GOP leaders have obediently swept up the glass, if sometimes after some initial grumbling. That pattern of deference could help explain why Trump might imagine Republicans would ultimately defend him even if he fired special counsel Robert Mueller, as he’s reportedly mused this week.

The decision to lock arms around Trump over Russia and Flynn reinforces the implications of the agenda congressional Republicans are pursuing. In both chambers, GOP leaders have rejected even pro forma negotiations with Democrats to order to advance a legislative program centered on repealing a wide array of Obama-era actions. Trump’s executive orders have likewise centered on undoing his predecessor’s regulations program, particularly those limiting the carbon emissions linked to global climate change.

Recent national polls found that almost three-fifths of Americans opposed both the House-passed legislation to repeal the ACA and Trump’s decision to withdraw from the Paris climate treaty. Each, however, drew more support than opposition from self-identified Republicans (although about one-fourth of even Republicans opposed each idea). Likewise, in one poll, while about two-thirds of Republicans supported repealing financial regulations, most Americans opposed the idea.

Republican Representative Tom Cole of Oklahoma, a shrewd former campaign strategist, told me the GOP believes enthusiasm for these ideas from their core supporters matters more for 2018 than the overall public resistance to them. “People know the Democratic base is extremely agitated, and you are not going to defuse it in the short term,” he said. “You’ve got to keep your own base charged up and the only way to do that is deliver [on these issues].”

But GOP members in more competitive House seats—starting with the nearly two dozen in districts that voted for Hillary Clinton in 2016—can’t win simply by mobilizing Republicans. And both by defending Trump’s actions on the Flynn investigation and pursuing such a polarizing agenda, they risk unnerving voters uneasy about both. With Trump lurching from crisis to crisis, the decision by congressional Republicans to bond with him so tightly could magnify their greatest danger in the midterms: that ordinarily Republican-leaning voters, especially in white-collar suburbs, will conclude they need a Democratic Congress to exert more oversight on a volatile president.

Whatever strategy Republicans pursue, Trump will loom large in 2018. In the past three midterm elections, exit polls found that 82 percent to 84 percent of voters who disapproved of the incumbent president’s job performance voted against his party’s House candidates. And between 84 percent and 87 percent of those who approved of the president’s performance voted for his party. But in each case, because the president’s approval rating among voters fell well below 50 percent at the time of each contest, his party suffered big losses.

Fewer competitive seats today will make it tough for Democrats to achieve gains of that magnitude. But the most recent national Quinnipiac University national poll showed public attitudes intensifying this midterm trend: Nearly nine in 10 voters who disapprove of Trump said they preferred that Democrats control the House, while over nine in 10 voters who approve want Republicans in charge. The GOP’s problem is that Trump’s disapproval rating touched 60 percent in Gallup polling this week, while his approval rating remains stuck below 40 percent. In almost everything they are doing, congressional Republicans are taking the high-stakes risk of speaking almost exclusively to that smaller group—and widening their distance from the larger one.