Today, House Democrats and lawyers for former President Trump filed their Trial Memorandum and Answer in the upcoming impeachment trial of former President Trump.  The legal arguments in these documents raise important issues, such as lack of jurisdiction and due process. 

On jurisdiction, former President Trump's lawyers argue in their response:

The Senate of the United States lacks jurisdiction over the 45th President because he holds no public office from which he can be removed rendering the Article of Impeachment moot and a non-justiciable question.

In the Democrat trial memorandum they cite no direct precedent on point to address this and resort to arguments like the following regarding the 1912 impeachment of Circuit Judge Robert Archbald:

Of the thirteen articles of impeachment that the House approved, six addressed conduct in his former role as a district judge.  In the end, Judge Archbald was convicted on five articles relating to his tenure as a circuit judge; on that basis, he was removed from office and disqualified from future officeholding.

This is weak sauce for two obvious reasons.  First, Archbald was removed from his current position as a Circuit Judge based on conduct in that position.  Second, even if they had convicted him of conduct in his former office, it would result in removal from his current office and both were in his role as a judge. 

Even if you get past the jurisdictional problem, there is another issue: due process.  Former President Trump is being denied the most fundamental rights provided to any defendant:

The House of Representatives deprived the 45th President of due process of law in rushing to issue the Article of Impeachment by ignoring it own procedures and precedents going back to the mid-19th century. The lack of due process included, but was not limited to, its failure to conduct any meaningful committee review or other investigation, engage in any full and fair consideration of evidence in support of the Article, as well as the failure to conduct any full and fair discussion by allowing the 45th President’s positions to be heard in the House Chamber. No exigent circumstances under the law were present excusing the House of Representatives’ rush to judgment. The House of Representatives’ action, in depriving the 45th President of due process of law, created a special category of citizenship for a single individual: the 45th President of the United States. Should this body not act in favor of the 45th President, the precedent set by the House of Representatives would become that such persons as the 45th President similarly situated no longer enjoy the rights of all American citizens guaranteed by the Bill of Rights. . . .

As this section concludes (emphasis added):

The House had no reason to rush its proceedings, disregard its own precedents and procedures, engage in zero committee or other investigation, and fail to grant the accused his “opportunity to be heard” in person or through counsel – all basic tenets of due process of law. There was no exigency, as evidenced by the fact that the House waited until after the end of the President’s term to even send the articles over and there was thus no legal or moral reason for the House to act as it did. 

Jurisdiction and due process are important cornerstones of the legal process and a fair trial.  They should not be ignored.