As Congress prepares to return amid a weekslong impasse over the next steps in President Donald Trump's impeachment, Democrats said Sunday that there is no rush to turn over the two House articles of impeachment to the Senate but that the holdout would not be "indefinite."

"I don't think it's going to be indefinite, no," House Intelligence Committee Chairman Adam Schiff, D-Calif., said on CNN's "State of the Union." "I don't think that's at all the desire, motivation here. The desire is to get a commitment from the Senate that they're going to have a fair trial, fair to the president, yes, but fair to the American people."

House Speaker Nancy Pelosi, D-Calif., said that as it stands, she is waiting to see what trial process the Senate settles on before transmitting the articles to the Senate. No trial can begin until the articles come through.

Senate Majority Leader Mitch McConnell, R-Ky., has said he wants the Senate to conform to the precedent set in 1999, during President Bill Clinton's impeachment trial, which included a two-resolution process: first, an initial agreement to hear the case and then a vote later on whether to call witnesses.

Senate Minority Leader Chuck Schumer, D-N.Y., disagrees and has pushed for a single resolution that would set parameters for presenting the case and allow for the calling of witnesses. Schumer wants the Senate to call four witnesses, including former national security adviser John Bolton and acting White House chief of staff Mick Mulvaney, to testify about Trump's conduct toward Ukraine.

McConnell lamented on the Senate floor on Friday that Pelosi was "trying to dictate our process," which he called "obviously a nonstarter."

Trump was charged in the first article of impeachment with abusing his power by pushing Ukraine to investigate former Vice President Joe Biden, his son Hunter and other Democrats while withholding nearly $400 million in military aid to the country, in addition to an official White House visit for Ukrainian President Volodymyr Zelenskiy. The second article charged Trump with obstructing Congress' investigation into those efforts.

The holdup, Schiff said, has succeeded in "flushing out McConnell" and in "showing that he is working in cahoots with the president." In an interview with Fox News in December, McConnell said he would work in "total coordination" with the White House on the impeachment trial.

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"So the American people needed to see that, and now they do," Schiff added, saying the Republican leadership doesn't "even want a verdict" but "a dismissal" of the charges.

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Speaking on ABC's "This Week," Schumer said "the focus will be on four Republican senators" once the articles are transmitted.

While a two-thirds vote is needed to convict the president, decisions about the trial process will come down to simple majority votes. Four Republican defections on any trial matter, including whether to call certain witnesses, could give Democrats enough votes.

Four "Republican senators can join us," Schumer said. "We have the ability to require votes on the four witnesses we have asked for, whether there's an agreement or not. We have the ability to ask for the documents.

"And I hope, pray and believe there's a decent chance that four Republicans will join us," he said. "If they do, we will have a fair trial."

Some moderate Republicans, like Sens. Lisa Murkowski of Alaska and Susan Collins of Maine, have suggested that they're open to hearing from witnesses.

Asked by ABC's George Stephanopoulos why he disagreed with McConnell's position to simply abide by the process during Clinton's trial — which he supported at the time — Schumer said, "The Clinton model is totally different."

"One, they had been heard from already," Schumer said of the witnesses sought in Clinton's trial. "Every one of those witnesses had been heard from before."

Schumer said the four witnesses Democrats want to hear from now "are eyewitness to the main charge against the president, that he withheld the aid for political benefit to himself."

Trump has lambasted Democrats for withholding the articles from the Senate, tweeting last month: "The Radical Left, Do Nothing Democrats said they wanted to RUSH everything through to the Senate because 'President Trump is a threat to National Security' (they are vicious, will say anything!), but now they don't want to go fast anymore, they want to go very slowly."

"Liars!" he added.

In an interview on "Fox News Sunday," Sen. Chris Van Hollen, D-Md., said Pelosi would submit the articles "when she feels it's appropriate."

Asked whether it's appropriate to hold an impeachment trial amid rising tensions with Iran, Van Hollen said Congress can do both.

"Our country will have to deal with both these issues at the same time," he said.