Based on the initial public reactions to the whistleblower's report from Congressmen on both sides of the aisle, it's not looking like there's any silver bullet dooming Trump. Maybe Democrats will unearth something else during their investigation process and, quite possibly, it frankly wouldn't surprise me if Trump has withheld / omitted parts of the puzzle to date. At any rate, I foresee no groundswell in favor of impeachment barring something that truly indicts Trump. However, what could trip up Trump is process - if it is later revealed that he squashed or altered any evidence, that would be his death knell. Remember, what doomed Nixon wasn't the crime, but rather the covering up and obfuscation of the crime.
So witch hunt till they find something that will prevent him from re-election in 2020 cause the Dems can't find anyone to beat Trump in the election. Got it.