The Republicans could refuse to allow witnesses next week and then vote to dismiss, that would end it. The Republicans may likely pay a big price for that., and I suspect some are unwilling to support it, will there be four who are unwilling? This may also be what the Democrats secretly hope will happen, setting up the argument going into the election that Republicans can’t be trusted to protect us from a radical and unstable Trump. That argument won’t work on the die hard Trumppers, but what about the moderates?
Then there is option 2. Less likely than what I’ve outlined above, but it’s possible 4 Republicans vote to allow witnesses, like Bolton and Mulvaney. The result would be a months long protracted slug fest in and out of the courts, with an unpredictable result sometime much closer to November. The effect on the election would by much less predictable. The unpredictability for both sides is why I think they will go for option one.
The American people deserve, either way it swings the pendulum, to have all the facts, and thus we deserve option two! The Senators crave preservation of their power so we will more likely get option 1.