WASHINGTON – President Trump is on a collision course with the Supreme Court, a trajectory that threatens to put the justices in the middle of the 2020 election.

Disputes over congressional subpoenas for documents and testimony, as well as legal battles over administration policies and Trump's businesses, finances and personal affairs, are moving inexorably toward a court Trump has sought to shape in his image.

In one box are myriad disputes over immigration, as well as health care and transgender troops in the military. In another are lawsuits seeking to pry open – or keep secret – Trump's business dealings, financial records and tax returns. Even his Twitter account is a target.

Most recently, the president's vow to fight all subpoenas from House Democrats and Attorney General William Barr's refusal to testify before a House panel have threatened to add another layer to the looming high court showdown.

Some battles already have reached the justices. They ruled narrowly last year in favor of the president's travel ban on several majority-Muslim countries. They seemed inclined last month to allow the Commerce Department to add a question on citizenship to the 2020 census, again by the slimmest of margins.

The question now is how many hot-button squabbles the high court will settle or sidestep in the 18 months remaining before Election Day.

Several factors may delay or derail many of the confrontations. The wheels of justice turn slowly. The Supreme Court turns down 99 of every 100 cases that come its way.

And the justices likely want to stay "three ZIP codes away" from political controversy, as their newest colleague, Brett Kavanaugh, put it during his confirmation hearing last year.

"All these cases are long shots for multiple, independent reasons," said Stephen Vladeck, a law professor at the University of Texas who follows the high court closely. "If this is a one-term presidency, the clock will run out while these cases are still percolating."

The likelihood that the Supreme Court will face a flurry of Trump-related cases increases exponentially if he wins re-election, however. Second terms tend to be litigious; think Richard Nixon's Watergate scandal and Bill Clinton's Whitewater investigation. If Democrats retain control of the House or win the Senate in 2020, the collisions could come in bunches.

Special interest groups challenging Trump up and down the federal court system hope they don't have to wait that long.

“I think it could be next year that we get the beginnings of the Trump rule-of-law docket,” said Elizabeth Wydra, president of the liberal Constitutional Accountability Center. "You don’t want the court to essentially sit on these issues simply to avoid grappling with the tough questions."

Mixing politics and law

Since Kavanaugh's high-wire confirmation last fall, the justices have sought a lower profile, although not always with success. That's particularly true for the nation's 17th chief justice, John Roberts, who shuns mixing politics and the law.

For three months, the court has been sitting on a Justice Department petition to end protections for undocumented immigrants brought to the United States as children – as if the court is waiting for the White House and Congress to negotiate a compromise.

Following that case in lower courts are others challenging immigration policies on asylum, temporary protections and families separated at the border.

The administration has lost a series of court decisions in its effort to withhold funds from local governments that refuse to help federal immigration authorities. Now it faces a handful of lawsuits over the use of emergency funds to build part of a wall along the southern border.

Lurking in federal appeals courts are lawsuits challenging the Affordable Care Act passed under President Barack Obama in 2010, which the Supreme Court has upheld twice before, as well as federal policies restricting access to abortion and contraception services.

The justices weighed in earlier this year on Trump's partial ban on transgender troops in the military, ruling along ideological lines that it could take effect while lower court challenges continued. The broader policy switch still may reach the justices in the future.

On that issue and others, the Trump administration's chances of legal salvation are better at the high court than many of those en route. Its conservative majority, bolstered by Kavanaugh's replacement of retired Associate Justice Anthony Kennedy, likely will be sympathetic toward executive branch authority over immigration and national security policy.

"I think these are all plausible cases for the administration," said Eugene Volokh, a prominent conservative professor and blogger at UCLA School of Law.

Roberts, in particular, "thinks the court should play an important role in resolving legal questions," Volokh said. "It’s hard to do that if you punt on those legal questions."

'A very different world'

Lawsuits involving Trump's tax returns, hotels and golf courses, and private life are less likely to be considered by the high court during the 2020 campaign. But that won't stop challengers from trying.

Subpoenas from House Democrats seeking testimony and documents, including a redaction-free copy of special counsel Robert Mueller's report on Russian interference in the 2016 election, are expected to result in protracted negotiations. The same goes for the battle over Trump's tax returns.

Democrats continue to press their case that Trump violated the emoluments clause of the Constitution by doing business with foreign governments while in office. A federal appeals court in Virginia appeared skeptical of that challenge during a hearing in March. But U.S. District Judge Emmet Sullivan ruled Tuesday that Democrats in Congress can press ahead with allegations that Trump is violating the Constitution's ban on foreign gifts and payments.

A federal appeals court in New York, meanwhile, is nearing a decision on whether Trump had the right under the First Amendment to ban followers from his Twitter account.

"Many of these cases may not make it all the way to a merits decision at the Supreme Court if Trump's is a one-term presidency," said Joshua Matz, a lawyer and legal blogger who co-authored a book on impeachment last year. "If Trump's is a two-term presidency, then we’ll be living in a very different world."

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