I am in the middle of reading a book, called A Mad Catastrophe by Geoffrey Wawro, about the decline and collapse of Austria-Hungary. So far it is mostly about how Austria-Hungary's military wasn't up to snuff, but in there are mentions about politics in the Habsburg Empire—a bureaucratic nightmare.
A major point I've noted in the book is how the Austrian portion of the empire kept conceding political power to the Hungarian minority, which made up about 20% of the population.
According to the book, there was a separate Hungarian parliament or Senate equivalent that had to accept proposals from the Austrian portion of the government. The Hungarian political groups constantly stalled any government action unless it benefited the Hungarians, and would especially reject anything that benefited Austrian political, economic or militaristic power at the expense of Hungarians.
I feel this may be a possible future in America as we descend into tribal politics. We already see how historic Americans have ceded power and influence to minority groups, and those groups exercise their muscles more and more, such as the Mexican President visiting California
The Austro-Hungarian experience is a topic for VDARE.com to pursue. It shows that majority-minority governments or even groups of ethnicities glued together do not live in harmony.
I know VDARE.com and other Dissident Right blogs stress this, but pointing to historical examples may help hammer the point in.