I believe how it works is that if the letter is not responded to, it becomes a subpoena. If that's not responded to, it becomes either criminal or civil contempt of Congress. Bear in mind that this senator is chairman of the Senate Finance Committee.

https://legalclarity.org/what-is-the-penalty-for-refusing-a-...

https://www.senate.gov/about/powers-procedures/investigation...

It Crapo's serious, he can try to recruit some other Republicans in congress and start making some noise. There must be at least a few who are particularly keen on privacy issues and/or care about their constituencies SS checks. And these are issues that are easy to scare voters with, and can rile up both party's bases and independents. Plus, everyone hates Musk.

But that'll never happen, because Trump won't allow it and his party has become slavishly obedient to his every whim. In any other Congress, DOGE would already be the subject of congressional joint investigation.

Senators, especially committee chairmen, have quite a bit of implicit leverage, beyond the direct leverage of subpoenas or directly cutting funding to an offending agency.

Any given Senator is to some extent constantly in a favor-trading game with executive branch officials. People from the President on down need congressional cooperation to get their pet provisions into bills, programs funded, nominees approved, etc. A Senator can tell a White House official "I'd love to help you with that, however I have this issue with this agency not responding to my requests". Assuming it's a reasonable thing, whoever at the agency is in charge of this then gets an irate call from their boss's boss's boss ordering them to cooperate.

Of course this mostly doesn't actually get played out, because everyone understands the dynamic that defying senatorial requests will ultimately cost the President in terms of cooperation on other issues. So the norm is mostly to comply with reasonable requests, unless you're quite sure that it's a top-level priority where the White House really wants to take a stand.

> there's not really anything the Senator can do to force a response.

As a chairman of the Senate Finance Committee, he can call SSA head for a senate hearing, which he can’t refuse

>> involuntarily resigned

> I'm curious what this actually means.

See perhaps "constructive dismissal":

* https://en.wikipedia.org/wiki/Constructive_dismissal

A work environment is made hostile to the (mental/physical/emotional) well-being of a someone such if they want to stay safe/sane they have to leave.

> involuntarily resigned

A bit further down in the article

effectively forced him from his role as chief data officer