Perhaps, but it's not politics in the US that causes there to be two parties, it's the mathematics of the voting system.

Since a plurality always wins each seat, if three significant parties exist, it is always in the benefit of two parties (usually the 2nd and 3rd) to join forces. Which just reduces things to two parties again. For example, if the Democratic candidate was polling at 40%, the Republican candidate at 35%, and a Libertarian candidate at 10%, it makes sense for the Republicans and Libertarians to join forces to get 45% and beat the Democrats. (Replace Libertarians with evangelical Christians and you have a fairly accurate representation of the last two presidential elections.) This is basically what happens with coalition governments in many parliamentary governments, except the individual parties retain their identities, which means that changes in alliances are more easily possible.

If we either had a voting system not based on winner-takes-all, or a system where seats in Congress were allocated proportionally (so that if the Libertarians got 10% of the vote, they got 10% of the seats in Congress), this would be resolved. But that is unlikely to ever actually happen.