3 things to know as Democrats wrap Senate trial arguments, hand floor to Trump's lawyers

House Democrats on Friday wrapped up three days of opening arguments in the Senate impeachment trial of Donald Trump.

The late-evening gavel gave way for Trump’s team of lawyers to take the floor on Saturday to lay out their rebuttal – a day Trump griped was “Death Valley in T.V.” -- but was required under rules written by Senate Republicans.

Here are three things to know:

Trump’s legal team will likely bring up the Bidens

The president’s defenders will be given 24 hours across three days to make their case before senators will be allowed to submit questions in writing.

Trump lawyer Jay Sekulow said the legal team planned to present arguments for only a few hours on Saturday, describing it as a “trailer” of “coming attractions.”

“Next week is when you’ll see the full presentation, but there’ll be plenty to see,” he told reporters on Capitol Hill.

While precise details of their rebuttal remains under wraps, Sekulow and other Trump allies suggested calling on former Vice President Joe Biden and his son, Hunter, to testify could be critical.

Hunter Biden was a board member on a Ukrainian gas company called Burisma, when his father as vice president led an international push to fire a Ukrainian prosecutor widely seen by the State Department as corrupt.

Neither Biden has been formally accused of wrongdoing, although a senior State Department official testified that he warned Hunter Biden’s employment on Burisma’s board was an apparent conflict of interest.

Sen. Lindsey Graham said Friday that he thinks there should be an independent special investigation into the Bidens, much like there was into Trump and Russia.

“The bottom line here is we cannot have an America where only one side is looked at,” Graham said.

And while Democrats insisted the Bidens don’t have relevant information to the case, Sekulow said Democrats’ references to the Bidens during the trial allows the GOP to address them.

“They opened up the door as wide as a double door on the Hunter Biden, Joe Biden, Burisma issue,” Sekulow said. “I guess they figured that was their way of getting ahead of it. We will address it.”

A vote on whether to subpoena additional witnesses or testimony is still days away.

ABC News correspondent Devin Dwyer said he spotted on the desks of more than half a dozen GOP senators in the chamber research documents entitled “Burisma Timeline” in bold black letters with bright yellow highlights of important dates. It was not possible to make out the contents.

The same lawmakers each also had a copy of the nonpartisan Congressional Research Service’s Jan. 21 report entitled “Obtaining Witnesses In an Impeachment Trial: Compulsion, Executive Privilege, and the Courts.”

Trump allies shrug off recordings reported by ABC News

ABC News reported Friday that a recording appeared to capture President Donald Trump telling his associates that he wanted the then-U.S. ambassador to Ukraine Marie Yovanovitch fired.

Trump has the power to fire U.S. ambassadors. But noteworthy about this recording is that it was taken at a small gathering that included Lev Parnas and Igor Fruman -- two former business associates of Trump’s personal lawyer Rudy Giuliani who have since been indicted in New York on campaign finance charges.

The recording appears to contradict statements by Trump that he didn’t know Parnas.

"Get rid of her!" is what the voice that appears to be Trump’s is heard saying. "Get her out tomorrow. I don't care. Get her out tomorrow. Take her out. OK? Do it."

Trump’s lawyers said Friday they didn’t think the recording would have any impact on the case.

Trump was defiant and opted instead Friday to attend a rally opposing abortion access – the first president to do so for the annual march.

“The Do Nothing Democrats just keep repeating and repeating, over and over again, the same old ‘stuff’ on the Impeachment Hoax,” he tweeted. “They want to use up ALL of their time, even though it is the wrong thing to do. They ought to go back to work for our great American people!”

Democrats accuse Trump of obstructing Congress, while aiding Putin

Trump has embraced the theory that Ukraine – not Russia – was to blame for meddling in the 2016 election. While some Ukrainian politicians openly favored Trump’s political opponent, Hillary Clinton, U.S. intelligence has blamed Russia for launching a sophisticated, state-sponsored attempt to sway American voters by hacking emails and weaponizing social media.

On Friday, Rep. Adam Schiff, a Democratic impeachment manager and chairman of the House Intelligence Committee, called Trump’s actions on Ukraine a “breathtaking success of Russian intelligence.”

“You know it's not going to stop,” Schiff said of Trump’s actions. “The president just told one of the members of this body he still wants Biden investigated. It's not going to stop unless the Congress does something about it.”

Meanwhile, Democrats argued, the president hid his actions from Congress.

Rep. Sylvia Garcia, another House impeachment manager, asserted Trump “orchestrated a cover-up and he did it in plain sight.”

“The president spent time at rallies at press conferences and on Twitter trying to persuade the American people that the House’s inquiry was invalid and fraudulent," she said.

Rep. Hakeem Jeffries, also a House impeachment manager, put it this way: "President Trump tried to cheat. He got caught. Then he worked hard to cover it up."

ABC News' Devin Dwyer, Lissette Rodriguez, Trish Turner, Cheyenne Haslett, Ben Gittleson, Allison Pecorin, Katherine Faulders, John Santucci, and John Parkinson contributed to this report.