In December of 1998, the House of Representatives voted for the impeachment of William J. Clinton based on two charges: one for perjury for lying about his blow-job and the other for obstruction of justice for trying to cover-up the lie about his blow-job. The House voted 228 - 206 to impeach the 42nd President based on these two abuses of power and sent those two charges to the Senate where they failed to convict him.
If we can kick-out a President out for lying about something he was embarrassed about, then why the hell is Trump still living at 1600 Pennsylvania Ave? If you think that Donald Trump hasn't committed more egregious, very provable, hell STREAMABLE felonies and crimes against humanity, they you haven't been paying attention.
The Senate currently has a bipartisan commission to investigate the 2016 hack of the Hillary Clinton campaign. The CIA, FBI, NSA, and 3 other government agencies have all concluded that the hack was perpetrated by Russia in order to favor Donald J. Trump for President in the 2016 election. The Senate is currently looking to see if there was any cooperation or collusion from the Trump campaign with Russia to orchestrate these hacks and leaks of embarrassing information to undermine Hillary Clinton's campaign.
If they found evidence from either associates of the Trump campaign or from Trump himself asking the Kremlin to orchestrate these attacks, not only would be it be grounds for impeachment, but it would be grounds to charge them with treason. A crime so heinous that it is specifically mentioned in the U.S. Constitution saying "No person shall be convicted of treason unless on the testimony of two witnesses to the same overt act, or on confession in open court" and that " The Congress shall have power to declare the punishment of treason."
Well....this youtube video of Trump asking Russia to hack Hillary's Emails during a campaign rally has 384,529 views, so I think you found your two witnesses.
If this was a normal country, if this was a normal person - this video would be more than enough to convict Donald Trump of treason especially considering Trump's favorable policies towards Russia including claiming Vladmir Putin might be his "new best friend" in July 2013 when he hosted the Miss Universe pageant in Moscow and more recently that Russia "should take care of it" when referring to the civil war in Syria, a policy that every former-KBG officer could get behind.
The reason why the House of Representatives hasn't already voted for impeachment for a painfully obvious, and provable act of treason committed by Donald Trump himself, is because of the obvious reason: fucking politics is the only thing that they care about.
Democracy's future has never once crossed their mind. America's trust eroding away in institutions like the Justice Department, like Congress, like the Russian investigation doesn't bother House Republicans one bit. All they care about is that they have a Republican President, and they won't turn on a Republican until the political backlash begins to drown them.
Unfortunately, the threshold is no longer the two witnesses required for convicting some of treason, but rather a more desperately high threshold - what will scare Paul Ryan's legislative hammer enough to impeach a Republican President and stand-up for what is right?
Will it be the eventual release of Donald Trump's tax returns from 2014 that will reveal that Eric Trump (the dumbest - and my personal favorite Trump) was telling the truth when he admitted to a reporter that ""We have all the funding we need out of Russia"
Will it be the fact that Trump has had 5 senior White House advisors who withheld information about meeting with Russia on multiple occasions during the campaign? Or will it be the fact that Tillerson, Kushner, Manafort, Ivanka, the entire Trump Organization, and most of his senior staff have deep financial ties to Russia.
Will it be the conviction of Michael Flynn for refusing to report information about being paid by the Russian government and who was still in communication with them for no less than a dozen times during the 2016 campaign?
What will move Paul Ryan's gavel to impeach a Republican President? Do we have to grab that pipsqueak by the collar and say "This is not about Trump! This is about Democracy! This obviously impacted a national election where a dictator rose to power! Why can't you see that!?"
I am not sure what will scare Republicans enough to finally dump Trump, because if they need evidence to find collusion - youtube.com has enough information to build your entire case.