Political parties everywhere are starting to seem more similar because of the 'professionalisation' of politics. Politicians are groomed and trained, not found. Political parties go more by research groups than principle. The same thing is happening in other professions.
But in the case of Obama v Romney, I'm surprised people see this as 'more of the same'. I think something very different has been going on in the last few years. This is the rise of the Tea Party and a new willingness for politicians to refuse to support the mechanisms of government in any way at all, if that government doesn't suit them.
This matters because the US system (in my view) has a major flaw. It's bicameral with a Presidential executive. All 3 power bases have significant ability to at least block legislation if it doesn;t agree with them. Therefore for political progress to occur, all 3 need to cooperate to some extent.
However, in practice these power bases are not usually held by the same party at the same time.
That's where something different is happening. In the past, there was a convention for political compromise that allowed the president to pursue his agenda successfully. Today, with the influence of the Tea Party, there are many politicians who simply won't play ball at all. They won't play by the old rules. They insist on their way, or no way. This is the reason for the total log-jam over the US budget deficit, which is actually more fixable than the European crisis if there was some degree of political willing.
The Tea Party have been playing a game of ultimate brinkmanship. They are prepared to risk economic Armageddon rather than compromise. It seems to me that, for this reason, the victory of Obama is significant because it gives him new authority to break that legislative log-jam. What will be interesting from here is to see whether the right wingers continue to block legislation, even though they have lost the election.
In my view, whether you support the Democrats or the Republicans, what the Republicans have been doing in the last couple of years is serious because it undermines the successful functioning of the US political system itself.