This would surely be an improvement over the status quo. Such progress as there has been in combatting racism, sexism, homophobia and other forms of exclusion and oppression would be more secure; and the quality of political discourse would be much improved without the willful ignorance and flamboyant stupidity that Republicans have lately introduced into our public life.
Civil society might even recover some of the moral and intellectual common sense that we have been shedding since the Eisenhower days.
But would the extinction of the GOP put an end to the Reaganite (neo-liberal, anti-affirmative state) turn of recent decades? Would it reverse the accelerated depredations of the Bush-Obama era – reestablishing privacy rights, for example, or restoring the rule of law to pre-9/11 levels?
I don’t think so. Without Republicans leading the way, Democrats might not know exactly what to do. But, in time, they would probably figure it out on their own, and they are more than capable of keeping everything on the wrong track.