OP- I think there are three things to consider-
1- What is the content of the internship? My kids did a variety of Congressional internships at various levels/stages of their education. Responsibilities ranged tremendously-- staffing someone who is chair of an important committee (Ways and Means, Foreign Relations, etc.) is a very different experience from Constituent Relations (not implying it’s not important- but it’s a very different experience). For some, being aligned (at least in theory if not in day-to-day practice is important. You don’t want to be writing talking points to make the member MORE effective in winning colleagues over to his/her point of view if you vehemently disagree with that point of view.
But for other roles it likely won’t matter. Constituent relations- you are helping people whose veteran’s benefits suddenly stopped without warning or reason (either an administrative error or identity theft-- and your office will have a guidebook on what to do to get them restored); a constituent who needs to fly overseas for a parents funeral but can’t find their passport (again, there’s a protocol on how to handle); a HS kid interested in applying to one of the service academies, a Medicaid recipient who is having trouble getting a prescription paid for, etc.
None of these require you being ideologically aligned with your boss. These are entitlement programs which have relatively clear guidelines so that when a citizen calls the office, there are specific people who will know what to do and will teach you what to do. No ideology at all. So figure out what you’ll be tasked with doing and whether or not it will bother you. There may be 15 interns at any given moment- you won’t all be working on anything remotely political. There may be an intern whose entire job it is to distribute the coverage schedule for the paid staff (who is handling Comm’s overnight, who is handling transportation over July 4th weekend, etc.) which believe it or not is a full time job-- you put together the schedule, people call you to complain, you adjust the schedule, someone else complains. There’s an intern who has to know whose mother gets dialysis on Fridays so the staffer can’t cover Fridays; who is driving their kids to camp on which day so they can’t be available for Press briefings, etc.
2- How good are you at compartmentalizing? For me, I have a few “bright red line” issues that I just can’t cross without feeling icky and compromised. But otherwise, I’m OK. I’ve worked for and with people who I don’t agree with and it’s been fine; a couple of times it was really problematic and it’s been a good learning experience. You know yourself better than we do.
3- How long do you expect this 6 week or 8 week experience to “stick around with you”? If it’s just another thing you’ll do as a HS kid, I wouldn’t worry about it. Nobody gets a reputation for ANYTHING at age 16 or 17. If you are looking for something which will become the foundation for lots of other things in your life-- then it’s worth another think. But even then- you can turn lemons into lemonade. One of my kids worked for a politician who eventually resigned in a highly scandalous way. Nobody looks at an intern and thinks “this is the person who caused X” (good reason to make sure you don’t get romantically involved with ANYONE in the workplace!) Kid learned a lot being on the sidelines of this massive #$%^-show, and has talked about it in interviews in a “I learned what not to do” kind of way. Plus-- NEVER pick up the phone when caller ID says National Enquirer".
Good luck…