House Speaker Nancy Pelosi wants to finish the impeachment inquiry into President Donald Trump before the heart of the 2020 election, but she will likely need to do it without help from federal courts, which could take months to resolve any fight over presidential stonewalling.

A historic court showdown became more likely last week when the administration announced it wouldn't cooperate with the investigation. Although at least two State Department officials are testifying anyway, the White House continues to block access to documents and prevent testimony from other witnesses.

Democrats now must decide whether to ask a judge to enforce subpoenas seeking information about the president's push for Ukraine to investigate former vice president Joe Biden and his son, Hunter. Any court battle would probably drag the inquiry into the 2020 election year, and even if Democrats were to win, a ruling could come too late to make impeachment politically viable.

"Every member I've spoken to wants to see it wrapped up in 2019 in the House of Representatives," said Rep. Jamie Raskin, a Maryland Democrat on the Judiciary Committee. Given the potential for a long battle that ends in front of a conservative Supreme Court, "most of us don't want to put our eggs in that basket."

A House Democratic leadership aide said Pelosi and her fellow leaders aren't ruling out going to court in certain circumstances, but that they won't let litigation slow down the inquiry.

Not all cooperation has stopped. On Friday, former U.S. Ambassador to Ukraine Marie Yovanovitch was interviewed by three House committees even after the chairmen said the State Department, under White House direction, ordered her not to appear. Gordon Sondland, the American ambassador to the European Union, plans to testify Thursday despite the department's "current direction not to testify," his lawyers said.

On Monday, former National Security Council Russia expert Fiona Hill, who left the administration in August, is scheduled to appear. And officials familiar with the Intelligence Committee's plans said on Friday night that two other witnesses are expected to testify: Deputy Assistant Secretary of State George Kent on Tuesday; and State Department Counselor T. Ulrich Brechbuhl, on Thursday.

Democrats got a boost Friday when a federal appeals court in Washington ruled that Trump's accountants must comply with a congressional demand for eight years of his financial records. That case, one of several subpoena disputes already before the courts, wouldn't directly control the impeachment inquiry, though it could give the Supreme Court its first chance to weigh in on congressional probes of Trump.

Any new enforcement effort would have to climb three levels of federal courts. If the House won at the district and appellate levels, those rulings would almost certainly be put off until the Supreme Court could weigh in.

Democrats would push to expedite the case. But the timeline would be highly uncertain, depending in part on the perceived level of urgency, says Donald Ayer, a former deputy attorney general who has argued 19 Supreme Court cases.

"There are no time limits on decisions made by the district courts, and other courts as well," Ayer said. "And so how fast is the first decision going to be made, and then if it's going to be appealed, how fast is that going to happen?"

Once any case reached the Supreme Court, the justices would probably put it on a fast track to ensure a ruling by the end of their term in late June, according to Tom Goldstein, a Washington appellate lawyer whose Scotusblog website tracks the court.

"At the outside, you're talking it being argued and decided in eight months," Goldstein said. "I think the court will do whatever it needs to, if it's practicable at all, to get it decided before the summer recess."

But that could be way too slow for impeachment-eager Democrats. Even if the administration lost at the high court and then complied immediately, an impeachment vote might not take place until well after Trump secured the Republican nomination, with the Nov. 3 election only months away.

"I think they need to move expeditiously" to wrap up the inquiry, said Steve Elmendorf, former chief of staff to House Democratic Leader Richard Gephardt. "I think the scope and depth and breadth of the illegality around him means they cannot wait."

Dragging the fight into 2020 would enhance the Republican argument that Democrats are trying to steal the election, said John Feehery, former spokesman for Republican Speaker Dennis Hastert. It also could draw attention away from the Democratic presidential primaries next year and possibly erode public support for the impeachment push, he said.

"The further this drags out the more people lose interest," Feehery said. "They are trying to strike while the iron is hot on this Ukraine matter, which I think is nonsense, but they are actually getting some pretty good traction on that."

Congress also has the power to directly fine or arrest recalcitrant witnesses, but it hasn't used that authority for well over half a century.

Jim Manley, a former spokesman for Democratic Senate Majority Leader Harry Reid, said waiting for the courts could have some advantages.

If the Democrats win, "Trump is in a world of hurt," Manley said. "He either complies with the court rulings or is found in contempt of court. If the courts rule in Trump's favor, Democrats get a big target to get fired up about in November."

The Supreme Court can move quickly when it sees the urgency. The 2000 Bush v. Gore ruling, which resolved that year's presidential election standoff in favor of George W. Bush, came only four days after the Florida Supreme Court allowed ballot recounts that might have tipped the election to Al Gore -- and just six days before the Electoral College met to elect the president.

The case that led to President Richard Nixon's 1974 resignation took a little more than three months from a federal judge's subpoena to the Supreme Court ruling on July 24 ordering Nixon to turn over Oval Office tape recordings.

Nixon complied and resigned on Aug. 8 after the tapes showed he had sought to stop the FBI's investigation into the Watergate break-in.

Yet even the three-month Watergate timeline could be unrealistic in the current standoff. The Supreme Court directly reviewed a federal district judge's ruling in the Nixon case, bypassing the appeals court level. That's a step the Supreme Court takes only if it sees a case as being extraordinarily urgent.

“The Supreme Court is capable of moving as fast as it wants to,” Ayer said. But “it has to want.”