Their authority to shut down intelligence agencies is purely theoretical. Not only would they be able to discover any effort to do that while it was in progress, but they could threaten or destroy the congresspeople who were most indispensable to that effort.
It's slightly scary to think about how total surveillance works on the populace in general, but nobody has any interest in most people (and knowing surveillance is in operation is enough motivation to make people intentionally less interesting.) Politicians and corporate decisionmakers are and will be the most subject to surveillance and control through that surveillance.
Here's the thing though: blackmail only works if you let it. Not everything a Congressperson could have in the closet is going to get them in any way removed from office. Once the intelligence community actually makes any good on any type of threat, congressional representatives no longer have any reason to play ball.
In short, blackmail doesn't work on the shameless.
What? Blackmail doesn’t reveal itself as some news report saying “CIA reports that Congressman X did blah blah blah, therefore the CIA recommends that you should not vote for him in the next election and other Congressmen should not work with him”.
It appears as something like “Leaked photographs reveal scandalous behavior by Congressman X. This scandal destroyed his reputation in Congress leading to him being ineffective in Congress, and made him deeply unpopular with voters, which will lead to him losing his next election”.
This is kind of a moot point if the portion of Congress which disagrees with this doesn't have control of both houses. Which is how Congress is supposed to work (it's not supposed to be very fast) but I don't think the founders had Congress delegating rulemaking powers to executive authorities in mind.
The portion of Congress which disagrees with this doesn't have control of anything. One of them is Warren, and Pelosi was campaigning against Markey just a month ago.
If Congress wants to effect change, they can literally write new laws.
I'm far less convinced that their investigative and committee powers should be held in that high of a regard, they're too easily hijacked by partisan politics and often fail to have any meaningful impact.
If they're truly that concerned about the problem, then make it illegal for federal law enforcement agencies to buy data on suspects or investigative targets from third-party sources. If you don't definitively kill the market, then I suspect you might just be looking for a political hand out.
Surely Congress needs to be able to investigate these matters before writing new laws?
I'm finding it hard to understand why you wouldn't want congressional committees (i.e. the people who regulate the country) to have the power to investigate bodies established and funded by Congress. Can you clarify?
I mean. The endless hearings about Clinton's emails? The endless hearing about Benghazi? Obamacare? The endless hearings about Trump and Russia and election interference? Going futher back - McCarthy and communism, Howard Hughes and airlines. MLB and steroids? Virtually all Americans believe that some congessional hearings were just useless partisan exercise - they just differ on which ones.
I think the examples are self evident to most people who follow American politics. If you had indicated that you were a foreigner and indicated that you were asking for an example, not a clarification, I might have given a kinder response.
