Washington CNN  — 

Democratic lawmakers on Capitol Hill are barreling toward historic impeachment proceedings against President Donald Trump.

The floodgates opened this week after the release of a White House phone transcript and a whistleblower complaint indicating that Trump pressured the new Ukrainian president to interfere in the 2020 election by investigating Democratic candidate and former Vice President Joe Biden – and that the White House tried to cover up records of the troubling phone call between the two leaders.

Only two presidents have ever been impeached in US history.

Here’s what the next few months might look like.

Investigations continue

House Democrats have been conducting multiple investigations through six separate committees, but the impeachment inquiry will now focus on the Ukraine affair. House Intelligence Committee Chairman Adam Schiff, who is leading that probe, told CNN on Friday that there will be a “busy couple weeks” coming up despite a scheduled congressional recess, and that he expects subpoenas and witness interviews to take place “as expeditiously as possible.”

Critical to the investigation will be an interview with the whistleblower who filed the complaint, as well as other potential witnesses from the White House and possibly from Trump’s personal attorney Rudy Giuliani, who spearheaded the Ukrainian efforts. The whistleblower has requested anonymity, so security measures will also have to be worked out.

House Speaker Nancy Pelosi initially indicated that she wants the Democratic-run committees to wrap up their probes and submit their most compelling evidence of wrongdoing to the House Judiciary Committee. That panel is traditionally tasked with writing formal articles of impeachment.

Key votes in the House

Once the articles of impeachment are drawn up, it’ll be time for some key votes in the House.

The House Judiciary Committee will go first. They need to approve any articles of impeachment before the full House takes a vote. According to CNN’s latest tally, the vast majority of Democratic lawmakers support the impeachment investigation, but that doesn’t automatically mean they’ll vote to impeach Trump.

As this plays out, analysts will watch to see who crosses party lines. Vulnerable Democrats in red states might hold out and vote “no.” It’s unclear if any Republicans will join Democrats and vote to impeach a sitting Republican president. Regardless, with Democrats in the majority, all signs point to the House eventually impeaching Trump and sending the case to the Senate.

The Senate takes over

Impeachment is a quasi-legal process. The impeachment articles approved by the House are an indictment against Trump. After the charges are formally approved, it’s time for the trial. Chief Justice John Roberts would preside over a televised trial in the Senate, and all 100 members of the upper chamber would serve as the jury. For a conviction, 67 “guilty” votes are needed.

Senator Majority Leader Mitch McConnell would play a central role in setting the rules for the trial. How many days will it take? How many witnesses can be called? Republicans control the Senate, so they’ll have the power to write the rules in any way that they deem appropriate.

Outside groups and super PACs could spend millions of dollars on TV ads around the trial. Liberal groups could encourage Republicans to break ranks, specifically targeting swing state senators with re-election races next year. Trump’s allies hoping to capitalize on the spectacle would be expected to hit Democrats for putting the country through impeachment instead of doing the people’s work.

No president has ever been convicted by the Senate during impeachment proceedings.

Trump awaits his fate

It’s safe to assume that Trump will be a major participant in the impeachment proceedings against him, even if he doesn’t appear at the Senate trial or answer questions under oath.

As impeachment chatter dominated the airwaves this past week, Trump unleashed dozens of vitriolic tweets, railing against House Democrats and even accusing Schiff of a crime without any evidence. He also re-tweeted dozens of supportive posts from Republicans and clips from Fox News. Trump and his allies have condemned the impeachment inquiry as another “witch hunt” with no basis.

This public relations strategy from Trump could keep Republican senators in line. But it also poses risks that his words could be used against him. Already, senior Democrats accused Trump of obstructing their inquiries and “witness intimidation” after he publicly criticized the White House officials who helped the whistleblower and hinted at using the death penalty.

The impact on 2020

With impeachment taking center stage, the Democratic presidential primary race will shift to the backburner. Most of the oxygen will be sucked up by what’s unfolding on Capitol Hill. But this shift is surely temporary – the Iowa caucuses are happening in February no matter what.

The Ukraine affair is about Trump’s alleged misconduct. But Trump’s underlying actions were all about prodding Ukraine to investigate Biden, dirtying up the Democratic frontrunner. It’s early, but Trump is trailing Biden by large margins in general election polls in pivotal swing states.

Republicans could turn the tables and try to turn the impeachment trial into a platform to highlight Biden’s supposed wrongdoing. Trump and his allies have been spreading debunked conspiracy theories about Biden and his son Hunter Biden regarding their actions in Ukraine.

Biden’s Democratic opponents are in a tough spot. They are outraged that Trump tried to get Ukraine to investigate Biden, but they don’t want the public anger to be so strong that it helps Biden secure the nomination. They will continue hitting Biden on the trail on policy issues, but they’ll need to steer clear of giving credence to the false attacks Trump spreads about Biden.