They have little to lose at this point. It won't upset their base, and they still dominate every section of government except for the executive. Trump is a dumpster fire, but if he was not in the equation, a GOP win this year would be quite likely.
I remember being very happy with the election and inauguration of Obama in 2008/2009, only to see the pushback and obstructionism destroy the image of his campaign, and very nearly his reelection chances.
So if Hillary wins this November, I'm sure many will celebrate and breathe a sigh of relief. But I really warn you guys to expect the worst in the next four years, both on the domestic and international fronts. Along with rampant obstructionism, expect rampant skepticism about anything Hillary does, even from those on the left. See, half the reason the people overlook Obama's policy faults is because he is very likable and charismatic, arguably far more so than Hillary. His image kills cynicism and skepticism far more than anything else, especially overseas, and I say this as someone who is not American.
Unless victory in November is a total landslide, like 350EV+, expect a very tired and uphill battle for Hillary, all in preparation for the inevitable challenge in 2020. In four years a lot can happen that is outside of Clinton's control; another recession, EU breaking apart, more "scandals" and so on.
The GOP could run a campaign simply based on the notion that "12 years of Democratic presidents have not helped, it's time for a change", and that may resonate very well, especially as people get tired of the political process. At some point people start ignoring policies and start voting for change for the sake of change; usually when governments have been in power for more than two terms.
There's a real danger that the anti-establishment strain we are seeing now will only become more powerful over time, and Hillary is literally the embodiment of the establishment at this point. Trumpism may die in 2016, or it may not, but the anti-establishment sentiment will remain.
That being said, the biggest obstacle to a GOP victory in 2020 is very much their own voter base. If they keep nominating more extreme candidates they will not make it pass the line, and even if the candidate is fairly moderate like Romney it is problematic. Romney had to pivot from the primaries to the general and it did not work for him.
You could also argue that it's pointless to look so far ahead considering how unpredictable this year has been. Very true, I don't think anyone saw Trump coming.
BUT, I do remember reading posts on another forum in 2012 predicting the ingredients for the 2016 election perfectly. The poster stated how the demographic changes, the extremism of the Tea Party, faux outrage, made up scandals and "truthiness" was going to create a "monster" in 2016, which would then be outside of the party's control, and potentially fracture it.
