House Speaker Paul Ryan, R-Wis., has little choice but to defer to President Trump on proposals to grant legal status to illegal immigrants who participated in, or are eligible for, the Deferred Action for Childhood Arrivals program.

Midterm primaries are just weeks away. Texas votes on March 6, the day after deportation protection for the so-called “Dreamers” expires. House Republicans need political cover from Trump, an immigration hawk beloved by the GOP base, if they’re to risk crossing their most committed voters and supporting legislation that could provide amnesty to around 2 million people.

“In Republican primaries, the voters are overwhelmingly — about 3-1 or so — opposed to supporting illegal conduct by giving amnesty,” Rep. Mo Brooks, R-Ala., told the Washington Examiner.

Brooks is a member of the House Freedom Caucus, a group of about 40 conservatives that firmly opposes just about all forms of amnesty — even for individuals like the Dreamers, who were brought to the U.S. as children by their parents and had no hand in the decision to break the law.

He hails from a state, and district, that are representative of the strong opposition to protecting illegal immigrants from deportation that has developed over the years among grassroots Republicans. They are who tend to dominate Republican primaries for Congress.

That is why, despite public opinion polls that have shown broad support for legalizing Dreamers among rank-and-file Republican voters, Ryan has to be careful not to cross Trump with any immigration-related package he puts on the floor.

A critical tweet or comment from Trump could cause severe political repercussions for Republicans in their 2018 primaries.

“President Trump has unparalleled credibility with the Republican base on the immigration issue. If a bill is good enough for him, it will be good enough for them,” said Michael Steel, a Republican operative who worked for former House Speaker John Boehner, R-Ohio, during a period in which similar pressures thwarted the Ohio Republican’s repeated attempts to pass immigration reform.

Former President Barack Obama granted a limited population of Dreamers legal status via DACA, as long as they signed up, after years of resistance to formal legislation by congressional Republicans. The executive program, always constitutionally questionable, was ended by Trump last fall, in line with his campaign promises.

But Trump has offered to legalize the approximately 700,000 DACA participants, plus another million or so who would have qualified for the program had they signed up, in exchange for border security measures and cuts to legal immigration.

House Democrats and progressive activists are balking, claiming there are enough votes, if Ryan would only bring it to the floor, for more liberal DACA legislation, similar to some proposals that have bipartisan support in the Senate.

In that chamber, Senate Majority Leader Mitch McConnell, R-Ky., agreed to allow debate on a DACA bill that has no underlying legislative language and could in theory evolve into a package Trump opposes.

The speaker isn’t budging from his demand that any bill he green-lights receives the advance approval of the president.

“I don’t want to risk a veto,” Ryan told reporters during his weekly press conference.

Trump in the 2016 presidential race quickly jumped to the front of the pack in the crowded Republican primary by staking out the most aggressive position on illegal immigration. He opposed amnesty, vowed to step up deportations, and promised to build a wall along the southern border with Mexico.

Immigration hawks in Congress have for years been outnumbered by pragmatic conservatives who favor comprehensive immigration reform that includes permanent protection for Dreamers.

But the president has strengthened their leverage, and made virtually impossible, politically for any bill to be considered by the House that doesn’t have stamp of approval.

“It’s frankly political pragmatism, to say that the president needs to be on board,” Rep. Adam Kinzinger, R-Ill., said. “If we try to solve this and have a solution that the president opposes, it’s just going to actually continue to poison the well.”