It's the end of the unchecked, rubberstamped Trump era, but it's also the beginning of cornered, desperate Trump era. I expect the new era to be ugly, outrageous, and discouraging. Donald has never in his life experienced checks & balances. He's not going to take to it kindly. Plus, his re-election campaign starts NOW. I expect there will be plenty of ugly to go around for the next two years.
Trump's barely been able to function with a government that's been on his side and has been doing all it can to support him. Even Now he's going to have to face genuine opposition. Trump will not be able to handle it well. I expect the next two years will be the equivalent of listening to a toddler throw a screaming tantrum.
The President still controls our foreign policy, our courts, the executive branch, and a vast propaganda network.
The House will prevent him from repealing the rest of the ACA and gutting the social safety net further. But it won't do anything at all about the other disasters we've seen so far. Expect the ongoing crisis in Yemen, dismantling of regulatory efforts to stop climate change, taking over the courts with poorly qualified political hacks, using the military for political spectacle, harming immigrant children for sport, etc.
A beast is most dangerous when he's cornered. Trump has always been a master of media distraction. Without discussing the possible damage Trump and the Republicans in this Congress can and possibly will accomplish before the newly elected Congress is seated, we can expect the real ugliness to begin as soon as Trump and his Republican Party start feeling pressure from the various investigations now possible from Democratically chaired committees in the House.
Push will as it always does come to shove. The GOP will rally around their president, and Trump will do as he always does; ramp up the lies, precipitate an expanding series of crises to distract and deflect, and find scapegoats to feed the desperate fears of his base. The facade of a partnership between Trump and the R establishment will need to end. They know the demographics are within 10 years of permanently screwing them up the ass if they can't change the narrative quickly and totally,Trump and his army of wanna-be-Trumps do the Kochs no good in the future, and now they can't do much now.