In what ways do American governmental agencies violate the Constitution?

(My Answer in Quora)

There are a number of ways that they do this. The most obvious one is the mass surveillance program that the NSA has undertaken that has morphed into a violation of individual rights to privacy.

https://www.reuters.com/article/us-usa-nsa-spying-idUSKBN25T3CK

Another example is the way the FBI (most notably under James Comey) acted to undermine the Trump campaign.

You may have seen him on a prayer candle, but James Comey is no saint

New revelations have made clear the conclusion many of us had already come to: James Comey was a reckless and untrustworthy FBI director.

https://www.usatoday.com/story/opinion/2019/08/30/james-comey-fbi-memo-leaks-trump-inspector-general-report-column/2157705001/

Fortunately it backfired.

Trump Is Winning His War on the FBI

Within the Bureau, there’s an asymmetry that even those who seek to play by the rules cannot ignore.

https://www.theatlantic.com/ideas/archive/2019/09/fbi-trump-comey/597523/

Then there was this attack on an innocent civilian (Carter Page). The entire case was built on a stack of lies.

Trump-Russia Steele dossier analyst charged with lying to FBI

Igor Danchenko, who worked on a largely unsubstantiated 2016 dossier on Donald Trump, is arrested.

https://www.bbc.com/news/world-us-canada-59168626