If you’re concerned about Trump’s nominations, the most impactful thing you can do is to reach out to your US Senators and voice your opposition. A large volume of brief phone calls do make a difference at strategic times. Immediately after a nomination announcement is one of those strategic times, because they are figuring out how/whether to respond publicly. Democracy must be fought for even after elections have ended.
Contacting Senators from both parties also matters right now. The prevailing message in the media is that Dems need to cater even more to Republicans to win the next election, they need to hear your voice if you disagree with that.
The most effective phone calls take less than a minute: say your name, your city or ZIP code, and what you support/oppose, maybe a sentence on why. You’ll be marked down on a spread sheet that is discussed at the daily office strategy meeting.
Other actions like brief emails, meeting in-person at the district office, meeting in-person at the DC office, can also be effective, but take more time and energy. Emails aren’t always read right away like a phone call must be answered for example. And you generally need to make an appointment for an in-person meeting.
Some inside perspective:
You are talking to staff or an intern. You might be the hundredth call for the day. They’ve heard all kinds of shit, from long-winded conspiracy crazies to the most courteous and intelligent calls ever. Yelling at them or being a jerk will get you nowhere. Be prepared to state your case clearly and concisely. Your concern will indeed be noted and logged.
Do not call a congressperson that isn’t your own. They are not required to listen to you, you are not their constituent. Do not write a congressperson that is not your own. The letter is almost guaranteed to go straight into the trash.
The best letters go on the intern break room fridge to be enjoyed by all.
Even so, unfortunately the congressperson may not act in a way consistent with the majority of people’s calls and letters. Thank money and power plays in politics for that.