Trump’s attacks on US intelligence agencies can do a lot of harm. People in the US will not trust them and confide in them.
Foreign countries will also not trust the US with intelligence information. There are other reasons for that. Trump told Russians confidential intelligence provided by another country. Do you think “shithole countries” will want to help the US now?
Now, intelligence agencies may not want to provide confidential information to Congress because of the Nunes memo politics. Trump and Congressional Republicans have done lasting damage. Sad!