Trump is terrified of the Democrats otherwise he would cooperate.

[Kablooie]

The only reason to block Democrats from accessing information is that he's scared of people finding out what he's hiding.
Now that Pelosi has brought this out in public I think it should be spread far and wide that he's afraid.

If he were besieged with accusations of being weak and cowardly it might throw him off his game.

If his cowardice could become the dominant message it might begin to unsettle his base. They follow him because he is strong, brave and invincible. If popular opinion could shift to Trump being scared, cowardly and running to hide, some of his base might begin to doubt him and cracks in his base would be the first step to a real impeachment.