Switzerland is, by some definitions, an older democracy than the US, if we neglect the short period of time when Napoleon conquered it (as we would similarly neglect the US Civil War). The Haudenosaunee have also been, in important senses, democratically governed for centuries longer than the US has existed, though possibly not as long as Switzerland. And presumably many small tribal peoples have remained democratic for millennia, though it's hard to tell in the absence of written records.

It does seem very likely that the Republican Party will govern the US for decades to come, like Perón's party has governed Argentina in between the military dictatorships, or Chávez's party governs Venezuela.