For weeks, President Trump’s advisers have been preparing for the eventuality of an impeachment trial in the Senate, a process that could begin as soon as Wednesday.

Some aspects of how Mr. Trump’s team will approach the trial have yet to be determined, including whether it will seek witnesses and how much time it will ask for to argue its case. But the basic configuration of the team defending the television-savvy president in a made-for-TV congressional event has been established.

The two constants will be Pat A. Cipollone, the White House counsel, and Jay Sekulow, who has been Mr. Trump’s personal lawyer since 2017. Both are expected to have speaking roles during the trial.

“The truth is, we’ve been prepared to proceed as soon as the articles were adopted,” Mr. Sekulow said on Sunday. “We’ve been prepared, we are prepared and we will be prepared for any contingencies.”