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Throughout the 2020 presidential campaign so far, Bernie Sanders has rarely passed on an opportunity to criticize Mitch McConnell. And so it was in the most recent Democratic debate, when Sanders—the Independent Vermont senator—punctuated an answer to a question on impeachment with a jab at the Republican Senate majority leader.

Saying he looked forward to “a speedy and expeditious impeachment process,” Sanders added, “Mitch McConnell has got to do the right thing and allow a free and fair trial in the Senate.”

Though Sanders’ cynical take on McConnell is justified by all available evidence, he need not worry in this case, because the Kentucky Republican has already solemnly declared that he will devote ample time to a Senate impeachment trial, should articles of impeachment be passed by the House of Representatives.

But before you wonder whether McConnell has suddenly gone soft, don’t. His acquiescence here likely has more to do with realpolitik than a sense of moral duty. And that could cause headaches down the road for Sanders, Elizabeth Warren (D-Mass.), Kamala Harris (D-Calif.), Amy Klobuchar (D-Minn.), Cory Booker (D-N.J.), and Michael Bennett (D-Colo.)—the lucky 13% of the Democratic caucus currently vying to be their party’s nominee for president.

Sanders’ comments were referring, if obliquely, to a fear recently circulated among some Democrats that McConnell would employ Senate rules to brutal effect, smothering an impeachment trial before it had a chance to get underway. McConnell’s reputation as a master tactician willing to withstand any amount of heat to get the outcome he wants has only grown stronger since his unprecedented move to block debate on Merrick Garland’s Supreme Court nomination in 2016.

Some observers nervously posited that McConnell would open an inquiry, call a vote by simple majority on whether it should be closed on some alleged foible in the House articles of impeachment or the overall process, and then bring an abrupt end to the trial, dismissing the charges and in a sense exonerating President Trump. The rules governing impeachment trials are fairly vague, notes David Corn of Mother Jones, creating in effect “a blank check for mischief” that could “prevent a full airing of the case against Trump.”

The anxiety was further heightened when conservative Cal-Berkley law professor John Yoo appeared on Fox News making the different, yet equally eyebrow-raising, claim that the framers of the Constitution never intended for impeachment to occur during an election year.

So it was a surprise then that last week McConnell declared publicly that he would be bound by the Constitution to conduct a thorough trial of an articles of impeachment that came his way. In fact, he let his fellow senators and their staff know that they should expect a trial to last anywhere from six to eight weeks, and that the Senate would likely be in session six days a week.

Given where we are in the political calendar of the 2020 campaign, the dilemma for Democrats comes immediately into focus. The primary campaign kicks off with the Iowa caucuses on February 3, followed by the New Hampshire primary February 11, and crescendoing with the Super Tuesday primaries on March 3.

One scenario reported by Time’s Phillip Elliott has the House voting on articles of impeachment before Thanksgiving, and the Senate trial starting in December—though that seems less likely as more revelations about the administration’s dealings in Ukraine surface, providing Democrats with more fodder for more subpoenas, more document requests, and more testimony. (Then there are the additional potential delays if a group of House Republicans continued to interrupt closed-door testimony as they did this week.)

If the House vote and subsequent Senate trial moves to early 2020, impeachment would crash directly into the heart of the Democratic campaign—”effectively shackling the six Senators-cum-Democratic-candidates to their desks on Capitol Hill,” Elliott writes.

One can easily imagine Senators Sanders, Warren, et al, sitting in a Senate trial until late in the afternoon on the day of the New Hampshire primary, for example. And if the Senate is in session six days a week, how exactly would candidates make it out to Nevada for that state’s crucial caucuses on Saturday, Feb. 22?

Senators running for president have faced conflicts before, of course, though rarely on a matter that felt this grave. Then-Majority Leader Bob Dole famously resigned from the Senate to devote more time to his ultimately unsuccessful campaign to unseat Bill Clinton.

But even that option seems to be off the table this time around. Democratic voters want nothing more than for their standard bearers to sit in judgment of President Trump. Every ‘no’ vote counts to the rank and file, even if there’s an implicit assumption that there are still too few votes to convict the president. For frontrunners Warren and Sanders, who represent states with Republican governors, this avenue seems like a dead end.

Senators could in theory try to miss some of the proceedings, although at the start of impeachment they each must sign a formal oath saying they will take the process seriously. Skipping town for some retail campaigning would raise legitimate questions about how seriously they took that oath.

“The Senate needs a quorum to function,” says Alan Baron, a former special counsel on impeachment to the House of Representatives, who served during several judicial impeachment hearings in the 1980s. “It does not require full attendance, though the optics of not attending may not play well at home.”

Presuming the six candidates will park themselves at their ceremonial desks in the Senate chamber and sit through hours of impeachment debate, they probably will not have very many opportunities to create viral moments of the kind perfected by Rep. Alexandria Ocasio-Cortez (D-N.Y.), who has turned aggressive questioning during Congressional testimony into liberal catnip on social media.

Under the current impeachment rules, a senator’s role is in effect that of a juror and therefore limited in nature, with most of the action dominated by the chief justice who presides, the House floor managers who present the case for impeachment, and the president’s defense team.

“I don’t see them opening it up to wholesale questioning,” Baron says. “Every senator would feel compelled to get his licks in, no matter how inane or irrelevant the question, just to let the voters back home see him perform.”

In a sense, this could be a gift for the Democrats running who do not serve in the Senate—candidates like Vice President Joe Biden, South Bend, Ind., Mayor Pete Buttigieg, and perhaps a wild card like former Housing Secretary Julian Castro or entrepreneur Andrew Yang. They will be free to campaign, while their rivals are stuck in Washington.

Though even they may find it hard to cut through the noise. For if impeachment dominates the Senate, it will dominate the discourse, too.

For all the Democrats running for president, the challenge going forward may well be one they’ve grappled with all along: How do they effectively communicate what they want to do as president in an era when the drama emanating from the White House has a way of controlling each and every news cycle? We’re about to find out if they can.

How Mitch McConnell Could Use Impeachment to Scramble the Democratic Primary

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