Senate impeachment trials are rare and historic - the one unfolding now is only the third in the nation's history - and with them come security jitters in and around the Capitol building.
A large metal detector has been erected in the Senate workspace for reporters, and the press will be herded into velvet-roped holding pens outside the Senate chamber at certain times - a notable change from the normal rules of engagement on Capitol Hill, where journalists are largely free to roam the hallways to interview lawmakers.
Reporters have protested the tighter controls.
Besides pesky reporters, the senators who will serve as jurors in the impeachment trial will be on the lookout for aggressive protesters in Senate office buildings adjacent to the Capitol.
Lawmakers faced similar tensions in October 2018, when the Senate considered the Supreme Court nomination of Brett Kavanaugh, who faced allegations of sexual assault. At least one senator was impeded by protesters at an elevator.
This time, the sergeant-at-arms has distributed a card to all 100 senators that contains these phrases to defuse a confrontation from hostile passersby:
* "Please move out of my way"
* "You are preventing me from doing my job"
* "Please excuse me, I am trying to get to the Senate floor"
* "Please excuse me, I need to get to a hearing/meeting"
* "Please do not touch me"
If those do not do the trick, the beleaguered senator can always shout: "Help, Police!"