There are two interesting words. Revolution vs. Evolution.
The difference is speed. Revolution is quick. Evolution is slow. From the first bullet fired at Lexington and Concord (1975), to the last in in 1781 (but not officially over till the Paris Treaty of 1983) the American Revolution took six (or eight years if you use the treaty). But that's war, not politics. The political revolution was over by the time the war started. The first political protests started in 1764, when the Sugar Act and the Currency Act taxed sugar and outlawed colonial money printing. So the revolutionary war took six years, but the revolutionary politics from Loyal British colonists to Patriotic American freedom fighters took eleven years. As a side note, the Law Revolution started in 1981 with the Articles of Confederation, and ended in 1788 when it was ratified by nine of the original 13 colonies, and thus took seven years.
Nowadays wars and laws usually are quicker. Transportation and communication is a lot faster. But the point is that revolution is quick and evolution is slow. Political evolution takes time. Ten years is revolutionary speed. So fast that it is a political revolution (often with a military one to follow).
Most major shifts take twenty years or more to occur. Also known as a generation. People don't change their politics, their children do. Each generation can only end a political argument that the last one started. You can't recruit your opponents, but you can convert their children before they grow up.
In other words, to misquote a famous cliche:
While generals fight the last war, politicians win the last cause.
There are a few exceptions, (usually caused by surprise violence/economic crisis) but most of the time, this works. The "Sixties" brought black voting rights, the "Eighties" we got black politicians. The "Oughts" got us a black President.
Prohibition started in January 29 of 1919, and ended on December 5th of 1933. In other words, it took just about 15 years. Pretty fast for a political change. Americans really missed alcohol.
The GOP is in flux right now, still undergoing change. Call it the T-Party evolution. It began in 2009, and will probably take 20 years to complete it. Assuming it works. Not all revolutions or evolutions succeed. The opposing principle may very well defeat the T Party.
But either way, the GOP will end up radically different than it is today.
The Democrats on the other hand are not undergoing a similar change. The "Occupy Movement", unlike the T-Party, abhors politics. They did not want to be co-opted. As such, it will probably take a longer time to for their movement to affect politics. It will still affect politics, just not as quickly.
It's not only policies, but mind sets are far more important. The Democrats have won some key battles in the hearts and minds, setting us up to win the political causes.
- A national healthcare policy was established, which means people will find out exactly what good healthcare can mean. If the program works, it will end the many lies the GOP told about it (death panels, etc.), which will lead to a win in the minds of voters. By demonstrating what real national healthcare is like, the minds will be convinced.
- The death of Bin Laden may finally allow us to break free of the culture of fear. We can stop trying to counter a terrorism threat that quite frankly was never that severe (more Americans were killed by motorcycles from 2000 to 2010 than were killed by terrorist attacks - yet motorcycles are still legal and I can't bring a regular tube of toothpaste onto a plane.).
- The Gay Rights movement has started winning battle after battle in the state courts, and even in a legislature or two. Instead of trying to stop new forms of anti-gay discrimination, we are finally getting rid of the most pervasive, long standing discrimination - the military's anti-gay provisions and the anti-gay marriage laws. This is major shift - and it reflects the shift in thought among the population.
The GOP on the other hand has won some smaller victories on the Abortion front, but nothing strikingly significant. More importantly, they are victories in Law, not in thought. They have repeatedly lost attempts to outlaw abortion outright, and instead have focused on making it more difficult and expensive to get it. While they have succeeded, by doing this, they are not winning the hearts and minds. Which is always the real battle. Minor victories get over-turned by big ones.