A step-by-step guide to what happens when the House sends the impeachment articles to the Senate

The procedures of an impeachment trial in the Senate are a mix of straightforward actions — like House managers walking the articles over to the other chamber and the Supreme Court chief justice swearing in senators as jurors — and a more complex set of rules, traditions and precedents that set out how the trial is conducted.

The latter are shaped through interpretations by the presiding officer, battles between the parties and the charged political emotions during a moment in history when an officeholder is threatened. No two impeachment trials play out exactly the same. While there have only been two impeachment trials for presidents, there have been many more for judges and other officials.

In other words, when the impeachment trial of President Donald Trump gets started in the Senate, some of the early steps seen on the floor will be obvious while others will be made as they go and won’t be so clear.

CNN spoke with former Senate Parliamentarian Alan Frumin, who is also a CNN contributor, to lay out the first steps of the impeachment trial now that House Speaker Nancy Pelosi is sending over the articles. While there’s a list of the steps below, Frumin stressed that there could be twists and turns along the way that will be dealt with in real time.

Frumin’s guidance is based largely on the “Rules of Procedure and Practice in the Senate when Sitting on Impeachment Trials,” which was last updated on August 16, 1986.

Here is Frumin’s shorter take on what to expect in the early stages of a Senate trial, which — like much of the congressional procedure in today’s Washington — is subject to change:

1. The House notifies the Senate that it has adopted articles of impeachment against an individual and has appointed managers to prosecute the case in the Senate. This will probably be done live on the floor of the Senate, although in certain cases it has been done by delivering the articles to the secretary of the Senate when the Senate was out of session.
2. The secretary of the Senate shall immediately notify the House that the Senate is ready to receive the managers for the purpose of the managers exhibiting the articles of impeachment — i.e. read the articles of impeachment. This message usually indicates to the House the particular date and time for the managers to exhibit the articles, generally arrived at in the Senate by unanimous consent.
3. Arrival of House managers pursuant to order of the Senate to “exhibit” (sometimes referred to as “present,” but meaning “read”) the articles of impeachment.
4. The managers are usually announced at the rear door of the Senate chamber by the secretary for the majority (currently Laura Dove, daughter of former Senate Parliamentarian Robert Dove). It is possible that this ceremonial function could be performed by the Senate sergeant-at-arms.
5. The managers are then escorted to the front of the Senate chamber by the Senate Sergeant-at-Arms. A podium with a microphone will be placed in the well of the Senate for the exhibition of the articles.
6. The Senate’s regular presiding officer (at this point it could be the vice president, the president pro tempore — GOP Sen. Chuck Grassley of Iowa — or another senator authorized by the Senate to preside) directs the sergeant-at-arms to make the following proclamation: “All persons are commanded to keep silence, on pain of imprisonment, while the House of Representatives is exhibiting to the Senate of the United States articles of impeachment against” the President.
7. One of the House managers reads the articles of impeachment.
8. The presiding officer then announces that “the Senate will take proper order on the subject of the impeachment, of which due notice shall be given to the House of Representatives.” This means that the Senate will notify the House when it will be ready to begin the trial.
9. The Senate will appoint an escort committee to escort the chief justice into the Senate chamber.
10. The escort committee will escort the chief justice into the Senate Chamber.
11. The Senate president pro tempore will administer the trial oath to the chief justice: “Do you solemnly swear (or affirm as the case may be) that in all things appertaining to the trial of the impeachment of Donald John Trump, President of the United States, now pending, I will do impartial justice according to the Constitution and laws: So help me God?”
12. The chief justice then administers the same oath to the Senators who are present.
13. Senators sign the Impeachment Trial Oath Book.
14. The Senate usually issues a summons to the impeached official, notifies the impeached to appear at the bar of the Senate at a time specified in the summons, and requests an answer from the impeached official.
15. The Senate usually requests a response (called a replication) from the managers to the answer of the impeached.

The Senate is expected to approve a resolution dictating the rules of the trial next Tuesday, when the trial begins in earnest after the Martin Luther King Jr. holiday. This resolution has been at the heart of the standoff between Pelosi, a Democrat, and Senate Majority Leader Mitch McConnell, a Republican. Pelosi insisted McConnell make public the rules — which appears set to pass without Democratic support — before she sends the articles over.

McConnell refused, arguing the House can’t dictate that to the Senate and how to run its trial. McConnell has made clear the rules will mirror those of the impeachment trial of President Bill Clinton in 1999 when the issue of whether to call witnesses or subpoena documents was made after opening arguments by the House managers and the President’s defense counsel.

And THEN the opening arguments of the trial can start. McConnell said earlier this week, the trial will begin in earnest on Tuesday.

Also worth perusing is a report by another Senate parliamentarian, Floyd Riddick, who, at the request of Sen. Robert C. Byrd while Watergate was unfolding, wrote an exhaustive examination of the procedures and guidelines of all the impeachment trials conducted to that point.