With the Supreme Court deciding to leave the controversy over President Trump's DACA deadline for lower courts to decide, the fate of dreamers stays in limbo. (Jenny Starrs/The Washington Post)

Take away a deadline, and Congress will simply lose its focus on any issue — even the heated debate around immigration.

At Tuesday morning’s House Republican briefing, just one of the five GOP leaders made a reference to the issue, and it was a passing one — a proposal meant mostly to placate conservatives, not a real solution that could get signed into law.

Across the Capitol, a few hours later, Senate Majority Leader Mitch McConnell (R-Ky.) and four senior Republicans did their weekly briefing. Topics ranged from gun background checks to the Winter Olympics. There was no immigration talk at all.

The four Senate Democrats who followed McConnell also made no mention of the looming Monday deadline to resolve the fate of 800,000 undocumented immigrants who have been shielded from the threat of deportation under an expiring executive order.

It’s understandable that most of the attention has shifted toward the fallout of the Valentine’s Day massacre of 17 students and faculty at a Florida high school, with the media intensely focused on gun laws and school violence.

Capitol Police remove a banner as members of the Catholic community and supporters of DACA recipients are arrested during a protest on Capitol Hill this week. (Saul Loeb/AFP/Getty Images)

All but one of the 17 questions fielded by House Speaker Paul D. Ryan (R-Wis.) and Senate Minority Leader Charles E. Schumer (D-N.Y.), at their separate press briefings, related in some way to the Parkland, Fla., shootings. The lone outlier focused on the memorial service for the Rev. Billy Graham.

This was supposed to be the week when Congress would force itself to resolve the dispute over the Obama administration’s Deferred Action for Childhood Arrivals (DACA) executive order, which President Trump announced in September he would revoke on March 5, giving Congress a six-month window to resolve the issue.

It was, in some ways, a masterful idea by the Trump West Wing, living up to his tough talk on immigration during the presidential campaign in 2016 but also foisting the issue into the laps of lawmakers.

But now, amid legislative and judicial gridlock, lawmakers and the media have moved on to other topics. First, the Senate failed two weeks ago to approve any compromise. Then, the Supreme Court declared it would not wade into the legal challenges to the DACA program until it plays out in lower federal court rulings — a legal process with no obvious end date in sight.

“We would be well advised to continue our work on it, but it seems to me that a lot of the air is out of the balloon here in the Capitol, and people don’t sense its urgency,” said Sen. John Cornyn (Tex.), the Republican whip who had been leading bipartisan talks.

Cornyn’s lead negotiating partner, Sen. Richard J. Durbin (Ill.), the Democratic whip, has declared helping the “dreamers,” as the undocumented immigrants who were brought here as children are known, an urgent, moral mandate. But even he understands why the issue has fallen off the radar.

Senate Majority Leader Mitch McConnell (R-Ky.) flanked by Sen. John Thune (R-S.D.), left, and Senate Majority Whip John Cornyn (R-Tex.), speaks with reporters this week about school safety measures in response to the Parkland, Fla., massacre that left 17 dead. The Republicans made no mention of immigration reform. (J. Scott Applewhite/AP)

“Along comes this tragedy, in the high school in Parkland, Florida, and the response of the young people and the national response of the subject, it blows away all other conversations about DACA and the Dream Act, North Korean nuclear threats,” Durbin said.

He and Cornyn have not held any serious immigration talks in weeks, he said — and he added that the same is true for a separate bipartisan group of centrist senators. And none are on tap.

“We talk but at this point we don’t have a plan,” he said.

Just like that, in the span of a few days — Senate gridlock, a madman’s bullets killing children and a judicial ruling — and the issue that consumed Washington for most of December, January and February is no longer worth a mention at a leadership news conference.

That’s not to say the issue has subsided from the political debate. Activists are trying to keep the pressure on Trump and Congress, with a rally planned for Sunday in Washington to draw attention to Monday’s DACA deadline that is set to pass without much fanfare.

In southwestern Pennsylvania, Republicans are furiously trying to stave off an embarrassing loss in a special election to fill a vacant House seat. The district tilted toward Trump by nearly 20 percentage points in 2016, a year in which Democrats did not even field a candidate against the longtime Republican incumbent, Tim Murphy, who resigned amid a scandal late last year.

Now, to halt the momentum for Democrat Conor Lamb, a GOP super PAC called the Congressional Leadership Fund has unleashed a new ad that ties Lamb to House Minority Leader Nancy Pelosi (D-Calif.) and her hometown San Francisco’s status as a “sanctuary city” for people in the country illegally.

“Conor Lamb wants to help Nancy Pelosi give amnesty to millions of illegal immigrants,” the narrator says. “Sanctuary cities and amnesty for illegals. Conor Lamb is a Pelosi liberal.”

Lamb, 33, a former assistant U.S. attorney, does support a path to citizenship for DACA recipients, but he has stated that he will not vote for Pelosi as speaker. That position was highlighted in a new ad he is running that calls for new leadership in both parties.

Clearly, Republicans believe the issue still has resonance with their conservative base voters, especially if it is mixed in with images of Pelosi. And Lamb seems to be aware of the threat.

But Republicans could face their own political dilemma if the federal courts rule that DACA was illegal, which would effectively reinstate Trump’s order and revoke protections from those 800,000 people. Deportations could begin quickly.

“I don’t believe that Senator McConnell and the Republicans want to see too many people deported out of Nevada and Arizona in the weeks and months ahead,” Durbin said.

He named two southwestern states with large dreamer populations where Republicans are trying to defend two Senate seats that could flip control of the Senate in the November midterm elections.

Republicans are well aware of the potential for a court ruling at any time.

“I’ve been working in and around courts long enough to know things can turn on a dime,” said Cornyn, who served as Texas attorney general, and on the state Supreme Court, before winning his Senate seat 15 years ago.

That said, Cornyn remains less than optimistic about congressional action until that court order arrives and forces action. Stating the obvious, he said: “We don’t do things around here unless there is a deadline.”

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