"Establishment" parties are under siege all over the "democratic" world.
Most recently, in Spain. There the Popular (conservative) party has the most seats in Parliament but needs the support (in coalition or for a minority government) of at least two other parties. Both they and the (establishment) Socialist party lost votes, the Socialists to Podemos, and the Populars to a centrist upstart party, the Citizens' party. The only possibilities seem to be a grand coalition of the establishment parties or a left coalition of Podemos, Socialists and Citizens', but Podemos, unlike the others, has supported a referendum on Catalan separatism, and seems willing to gamble that an early election would put them in an even stronger position.
http://www.thelocal.es/20151223/spains-ciudadanos-calls-for-pact-with-conservatives-and-socialists
A left coalition would resemble the one recently formed by Portugal, where the establishment governing party was a merger of the establishment conservatives and social democrats. Let me digress about social democrats. In the mid-twentieth century, social democrats won the support of the working class in Europe for two things: one, their resistance to Fascism, and two, their support of a labor-socialist position, that is, one that is both socialist and pragmatist. As time went on, the pragmatism took control, and social democrats turned in a conservative direction. In Spain and France, this division was within the so-called Socialist parties; but in Portugal a Socialist Party contested with the social democrats for the votes of the working class. Anyway, despite losing the election, the establishment tried their best to retain control of government. They could not, and a coalition of left parties took over and have changed the direction of the country. But it remains to be seen if they can succeed under the pressure of the European Community. A similar coalition in Greece could not. We may see new elections in Hispania in the near future; if so, the future there may look quite Italian.
[link:http://www.counterpunch.org/2015/12/01/portugal-the-left-takes-charge/|
http://www.counterpunch.org/2015/12/01/portugal-the-left-takes-charge/]
[link:http://www.britalypost.com/spain-is-facing-an-italian-like-political-instability/|
http://www.britalypost.com/spain-is-facing-an-italian-like-political-instability/]
In Italy, after a decade or more of chaos, an establishment center-left government took power two years ago. It has struggled and faces opposition from an insurgent "Five-Star" movement, antipragmatic but without any clear principles of its own, that sounds a bit like Donald Trump. They have won some city governments (with mixed results) but would challenge the establishment if elections were held soon.
[link:http://www.ft.com/intl/cms/s/0/45c62a88-99d9-11e5-9228-87e603d47bdc.html#axzz3vo3Y268R|
http://www.ft.com/intl/cms/s/0/45c62a88-99d9-11e5-9228-87e603d47bdc.html#axzz3vo3Y268R]
Could we see a coalition of establishment Republicans and Democrats in this country? Since we do not have Parliamentary government, coalitions are hard in this country, but there are some signs of it in the House. Or could Trump's run create something like a Five-Star antipragmatic unprincipled movement in the USA? No secret what I would like to see -- a government of a unified working-class left.