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So far, President Donald Trump has been sticking to Twitter to counter Robert Mueller’s investigation of Russian interference in the 2016 presidential election.

But following the indictment of two campaign staffers — along with disclosure of a guilty plea and cooperation agreement by a campaign foreign policy adviser — President Trump may be tempted to use the powers of the presidency to lessen his legal and political exposure.

With the news that Mueller may have enough information to charge Michael Flynn, a former national security adviser, the temptation may grow all the stronger.

One possibility is that he could fire special counsel Mueller, but he’d have to fire Deputy Attorney General Rod Rosenstein first — and possibly other officials too. That could get messy, fast. Reports indicate that Trump has also asked about the scope of his pardon powers. And in recent days, some key allies have encouraged the president to issue pardons of one sort or another, including a blanket pardon to all officials involved in his campaign.

It would be within the president’s authority to issue such pardons. Article II of the Constitution grants presidents broad power to issue pardons for federal crimes, a power that many legal scholars believe is unreviewable by courts.

If true, this presents a frightening situation: The president may retain a controversial, yet legal, way to obstruct the workings of our justice system.

But that doesn’t mean the Constitution leaves Congress without any power to check his abuses. If President Trump abuses his pardon power, Congress can fight back in two ways.

Congress could compel testimony of pardoned individuals by threatening them with civil contempt

The first way Congress could respond to unreasonable presidential pardons is to subpoena those who accept these pardons — that is, demand that they testify in public or private hearings.

If they refuse to testify, Congress could charge them with civil contempt. The pardoned officials might therefore face jail time.

How would this work? As many legal scholars have already noted, once an individual is pardoned, she is shielded from criminal liability. Since she can’t be charged with a crime, she gives up her Fifth Amendment privilege against self-incrimination, the privilege commonly known as the “right to remain silent.”

That means there is nothing preventing Congress, which has broad subpoena power, from asking pardoned individuals about their campaign activities, or activities since the election — including about any illegal activity in which they took part.

Some scholars have pointed out that individuals might only forfeit their right not to testify about the crimes for which they have been pardoned. That is, they can still plead the Fifth if asked about anything else. But even so, as in the Manafort case, the crimes charged may be plentiful, and so there might be plenty on which the pardoned individual could be asked to testify.

But what if these witnesses still refuse to testify? Congress has another card to play.

Presidents can’t pardon people held in contempt of Congress

If pardoned individuals refuse to answer questions, congressional committees can hold them in contempt of Congress, a form of civil contempt. When witnesses are held in civil contempt, they can be imprisoned until they agree to testify.

If Congress took this drastic action, couldn’t the president issue a second pardon to protect an uncooperative witness? Not quite.

In Ex Parte Grossman, a 1925 case, the Supreme Court carved out a narrow exception to the president’s broad power to issue pardons for federal offenses. Chief Justice William Howard Taft — the former president — explained that “a pardon cannot stop” the charge of civil (as opposed to criminal) contempt.

The distinction may be hard to grasp for nonlawyers, but what it means is that the president can arguably pardon criminal contempt convictions that aim to punish wrongdoers. In fact, President Trump recently pardoned Joe Arpaio for this very charge.

But the pardon power does not extend to civil contempt, which is used by government bodies to ensure that individuals comply with government directives, rather than as punishment for something they have already done.

Because contempt of Congress can’t be pardoned, Trump could do little to obstruct congressional committees from engaging in broad-reaching fact finding. Trump’s pardons may therefore embolden investigators to issue subpoenas and pressure pardoned individuals to talk.

In short, far from quashing the media’s interest in Russian collusion, the use of such pardons may keep the story in the headlines for the foreseeable future, threatening to (further) derail the Trump presidency.

The impeachment option

Congress could also impeach the president for drastic abuses of the pardon power. Just as Article II of the Constitution gives the president broad powers to issue pardons, Article I gives Congress broad powers to conduct impeachment proceedings and determine impeachable offenses — including misusing pardons.

The Supreme Court wrote in Grossman that “exceptional cases” in which the president seemed to be using his pardon power to obstruct justice “would suggest a resort to impeachment.” In fact, Congress cited President Andrew Johnson’s abuse of the pardon power when it first attempted to impeach him in the late 1860s. (Johnson pardoned Confederate leaders whom Congress had disqualified from leadership positions in the Reconstruction South.)

The founders themselves explained the rationale for permitting impeachment in such a case.

During his state’s convention for ratifying the Constitution, James Madison argued that impeachment ought to be triggered if the president obstructed justice through the use of pardons. His comments were clear: “[I]f the President be connected, in any suspicious manner, with any person, and there be grounds to believe he will shelter him, the House of Representatives can impeach him."

For Madison’s vision of the Constitution to make sense, Congress, our most representative institution, must be willing to consider impeachment of the president once the pardon power is abused.

Otherwise, the pardon power, itself a legal tool, could register a shocking blow to the rule of law: It would permit presidents to engage in criminal conduct with the intention of pardoning their co-conspirators.

In a caps-locked cry for help, President Trump recently deemed the Russia investigation a witch hunt, tweeting that someone should “DO SOMETHING!”

Given that level of apparent distress, he may be itching to take matters into his own hands. But President Trump ought to think twice before reaching for his pardon pen.

Far from shutting down the Russia controversy, pardons could begin a new contentious chapter that could end the Trump presidency.

Vinay Nayak and Samuel Breidbart are students at Yale Law School.

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