Have the Republicans changed from being conservative towards a club that is more interested in power than American citizens?

I remember when people like Eisenhower and Nixon were president. They were concerned with limiting government power but also concerned for the welfare of Americans and the American middle class. Even Reagan gave lip service to proper regulation and in working with the opposition party.

It seems that since Bush, the Republican leadership seems primarily concerned with gaining power, destroying all opposition, fixing elections, and protecting large corporations, even non-American ones. The changes they demand are totally financed by the middle-class and the poor. They purposely ruin, disrupt, or bankrupt regulatory agencies, and are prepared to shut down the American government even if it topples the world’s economy. Their tactics seem more like a political coup than an attempt to govern. They and their Supreme Court are striking continuous blows against democracy and favoring autocratic rule. I suspect that if they win the next election, Presidential powers will expand to unexplored heights and we will rapidly become a third world oligarchy.

Am I worried for nothing or is this the final chapter of the U.S. as a world class democracy?