“They can’t indict. Because if they did, it would be dismissed quickly. There’s no precedent for a president being indicted.”

So declared President Trump’s lawyer, former New York mayor Rudolph Giuliani, who eagerly recounted this week how special counsel Robert S. Mueller III’s team has assured Trump’s legal team that Mueller won’t try to indict the president while he remains in office — a decision based, presumably, on a long-standing Department of Justice policy that holds that a sitting president can’t be indicted.

Plenty of legal scholars, including me, disagree with the basis of that policy: Nothing in the Constitution bars indictment of a sitting president.

But even if Mueller opts to follow that questionable policy, it may not be the legal victory Giuliani seems to think it is. Trump might fare better if he’s indicted, and not impeached. Indeed, for Mueller, the question might only come down to the order, not the merits, of these actions. In other words, Trump could find himself both impeached and indicted. An impeachment can even make such an indictment more likely.

Under his mandate as special counsel, Mueller must follow the “rules, regulations, procedures, practices and policies” of the Justice Department. Arguably, that binds him to the department’s two Office of Legal Counsel (OLC) memos, neither of which has the force of law but which both support the principle that Trump can’t be indicted while in office. During the Nixon administration, OLC found that, despite acknowledging “troublesome implications” and “certain drawbacks,” “an impeachment proceeding is the only appropriate way to deal with a President while in office.” During the Clinton administration, OLC conceded that the question of indicting a sitting president was an open one but, ultimately, concluded that “neither the text nor the history of the Constitution” is “dispositive” on this question. Despite this finding, OLC explained that no indictment of a sitting president should be sought because of  “more general considerations of constitutional structure.” The OLC has a long history of supporting inherent executive powers, but this memo stood out as a superficial and self-serving (and mostly wrong) analysis: The Framers of our Constitution discussed presidential powers at length and in detail. There was no stated intent to create such a sweeping immunity in this one officeholder.

Trump’s new lawyer has not helped wind down the Russian election interference probe and may have entangled Trump in more legal trouble. (JM Rieger/The Washington Post)

But while many legal observers disagree on the underlying question of the constitutionality of indicting a sitting president, there is close to universal agreement that it is better for the country to have presidential impeachments precede indictments. This, however, is only a matter of sequencing. Even if Mueller does not seek an indictment for constitutional reasons, he could easily do so if Trump is removed from office or after the president completes his term. That sequence would work against Trump’s interests as a criminal defendant.

As the lead defense counsel in a 2010 impeachment trial in the Senate, I can say from experience that I would much prefer a client to be indicted first, rather than impeached. To start with, a defendant under indictment can avail himself of myriad constitutional and procedural protections that aren’t available in the impeachment process. In impeachment proceedings, the federal rules of evidence on issues including hearsay and chain of custody are discretionary, not binding. The ability to call witnesses, presentation of evidence and discovery are all left to the Senate’s judgment. Then there is the jury. There is no voir dire or vetting; the defense is stuck with 100 elected, career politicians who, in many instances, have already made public statements regarding your client.

Conversely, an indictment comes with a formal grand jury determination and set stages of the legal proceedings, from arraignment to pretrial to a trial with a real judge. Defense motions to address violations of the defendant’s First, Fourth, Fifth and Sixth Amendment rights are routinely heard and carefully addressed. Firm evidentiary rules — both statutory and constitutionally based — guarantee the timely disclosure, to defense lawyers, of evidence and witnesses known to government prosecutors. At trial, judges control witnesses to avoid prejudicial statements or testimony related to excluded evidence.

Not only is the criminal process fairer to defendants, but also the fact of a prior impeachment proceeding can be deadly for a later criminal defense. Faced with an impeachment, a president must decide whether to testify at the risk that anything he says can be used at a later criminal trial. And there’s the potential that in the course of impeachment proceedings, otherwise privileged or confidential information could become part of the public record and thus accessible to prosecutors in a later indictment. In Trump’s case, if the eventual report of the special counsel’s findings led to impeachment, Mueller could sit back and watch things play out, while gathering the fruits of the impeachment process to be used in a subsequent indictment. This includes getting a preview of the arguments and evidence the president would use to mount his defense. For Trump’s attorneys, that would be like playing a poker hand and then having the dealer say, “play the same cards, again, for real this time.”

If Trump were indicted, it’s unlikely he would face a trial during his tenure in office. It would be years before legal and procedural issues were fully addressed by the courts, including settling the question of any immunity from indictment while in office. Courts can be highly deferential to presidents and would likely schedule a trial after Jan. 20, 2021 (or Jan. 20, 2025, as the case may be). In past cases involving compelled appearances or answers from sitting presidents, courts have largely accommodated scheduling requests while refusing outright immunity arguments (as was the case this week, when Trump unsuccessfully sought to delay a defamation case brought by a former “Apprentice” contestant).

Moreover, if an indictment were to come before impeachment proceedings, that would give Republicans in Congress political cover to vote against impeachment under the rationale that they want to allow the courts to work through the issue. The president and his supporters in Congress could also claim that it would be unfair, and unduly burdensome, if Trump had to face both an impeachment and prosecution.

Of course, Trump doesn’t want to be indicted, at all. But if that happened first, it would offer him a broader measure of legal protection while offering maximum political cover to those opposing an impeachment bill. The federal statute of limitation for obstruction of justice, criminal campaign finance violations, false statements or criminal conspiracy — offenses likely being contemplated by the special counsel — is generally five years. Even if that statute began to run, let’s say, at the firing of former FBI Director James B. Comey in May 2017, the statute would not run out until May 2022. Since many of these potential charges would involve allegations of ongoing violations, the period would run long past 2022.

Any of these scenarios is a long way off: The special counsel’s office has been mum on the subject, Giuliani’s assertions notwithstanding. Trump’s party currently controls both houses of Congress and has shown little appetite for impeachment. Publicly, at least, and most importantly, a credible criminal case against Trump has yet to materialize, and the president is entitled to the same presumption of innocence enjoyed by all citizens.

But here’s a scenario Trump wouldn’t like: If Democrats regain control of Congress during his presidency, he could face impeachment proceedings during office. Even if he survived impeachment like Bill Clinton, Trump could find himself facing awaiting prosecutors with a ready indictment and detailed knowledge of his defense. The difference would be that his liberty, not just his office, would be at stake. It is not constitutional law, but the law of unintended consequences, that proves the most dangerous in presidential scandals.