News reports have focused on parallels with the populist strain of the U.S. political environment, but there is also a parallel with the tension around political structure, with important differences.
As part of the European Union, the U.K. is something of a confederation within a confederation. The vote to strengthen independence of the U.K. weakens the EU, but could weaken the U.K. based on the voting patterns within the U.K.
The vote in Britain calls back into question the vote for Scotland as a separate entity to remain with Europe, followed by less urgent and less likely possibilities for exit - Northern Ireland from the U.K. and Greece or others from the European community. The vote for Brexit is a vote to maintain and strengthen British sovereignty instead of submitting to an economic confederation of nations of Europe and associated institutions like the International Monetary Fund that collectively operate more and more like a political entity as those institutions evolve.
In the U.S. financial markets have been roiled by the Brexit vote, but the amount of disruption to the U.K. or even to Europe is a faint echo of the emerging instability of the political structure in the U.S. The American political breakdown is a more organic process which has not yet resulted in a severe political dislocation, but the signs are all there.
The Supreme Court is on edge with one vacant seat.
If the Republican presidential candidate wins the presidential election and appoints a justice to the court who is approved by a Republican-controlled Senate, that individual will be viewed as illegitimate by Democrats for that person's entire term. If, instead, the Democrats control the Senate, how do they consent to a nominee who is not to their liking now that the Republican's have set the precedent of complete obstruction of a nominee. The logical response would be to block any nominee who is not Merritt Garland.
If the Democratic presidential candidate wins the presidential election and the Democrats retake the Senate, the Republican-controlled Senate could end up approving Judge Garland in the lame duck term. Mitch McConnell has said this would not happen, but Garland is relatively conservative and old for a Supreme Court nominee. McConnell could argue that his caucus demanded this action and he bent to the will of his caucus. Still, if this happens, even though the action exposes the cynical ploy of refusing to hold hearings for Garland in the first place, it would have the effect of retroactively restoring a modicum of functionality to the three branches of government in distress - the President, to honor his original appointment, the Senate to hold hearings on that nominee after all, and the Court, to fill the vacant seat.
If Mitch McConnell and the Republicans stick to not having confirmation hearings in the lame duck session, with a Democratic president, this would afford them the opportunity to stall the program of the next president, either as the minority party, or as the majority in the Senate, depending upon the outcome. As stated in earlier posts, there is no reason to believe that with a President Clinton a Republican Senate majority would approve any candidate who is on the moderate to liberal spectrum. The argument would be that it is just so important to the country, which was the argument to shut down the government and even go into default -- it was so important to the country.
Any of the above Supreme Court scenarios could result in serious political tension that would lead to further instability in the U.S. and a serious dislocation.
The Candidacy of Donald Trump
The significance of the candidacy of Trump is that there has never been any major party candidate quite like this. That is clear, but there have been different viewpoints on how much this matters. If Trump wins the Presidency, that win becomes more dramatic than the Brexit referendum because Republican Party politics on the national level can never be quite the same again and Democratic Party politics will also require serious adjustments. If Trump loses, Republican Party strategists will go back and try to diagnose the problem and find solutions, but there will continue to be pressure on the tried and true campaign formulas that were wildly unsuccessful for establishment Republicans in 2016.
The Turmoil in Congress
Any semblance of institutional order in the House and Senate can be expected to continue its breakdown as noted here.
Ironically, on this day that Brexit is the big news, the NYT has an article that walks through the dysfunction within all three branches of government without quite pointing the finger as directly at the Republican controlled Congress, with the executive and judicial branches the victims, as we would find justified. Three Separate, Equal, and Dysfunctional Branches of Government.