^^ The rats under Nixon were subpoenaed, and it was the evidence some of them gave under extreme legal pressure that enabled the Watergate Senate Investigation Committee to subpoena Nixon, which led to his resignation.
They haven’t found enough evidence of collusion of the rats yet, so we aren’t there and may never arrive. Nixon went through most of his upper-level staff, three Special Prosecutors, two AGs, two FBI chiefs and two VPs before they finally got him. And Trump is not as smart, or highly trained in law as was Tricky Dick.
This has just begun. Sit back and enjoy your constitution at work.