Never in the history of putative democray/representative republicanism has a one-party system ever improved the function of government or the living conditions of a state's people. One-party rule is the hallmark of dictatorship.
And what we have now....in effect....IS a one party system. We are already there my friend and that is why America and the middle class is nearly exterminated by the elites. Many people are too brainwashed/hypnotized to see it.