If it did, then it would be a permanent minority party.
In the Democrat party, the leftists control the conversation.
In the GOP, things are good as long as the conservatives control the conversation - when the liberal Republicans start taking over, then there's trouble.
Every party needs its own "centrists" to remain electorally viable.
This is both the beauty and curse of the Founders’ theories.
For one party to get into power with a margin, they have to have members from the middle. Once one power gets close to a full majority, and people start saying things like “the Gop/Dems are a permanent minority”, you know things will shift back. As soon as I heard people say the Dems were a permanent minority I knew we were in trouble, just like when the shoeshine boy gives you a stock tip, it is time to get out of the market.
The Dems got lean and mean while the minority, and they rode the tide of events to power, just like the GOP in 1994. Then the GOP got the Big Tent and it fractures, while the other side is passionate and wants to win. The key point is when the rank and file of the majority party realizes their congress isn’t going to do much they want.
The only way to shift things is to move the middle psyche of the country one way or another to change what the middle actually is.
Rightly or wrongly, the Iraq war has given the Dems an opening. But the Dems handling of Energy and possibly mortgage issues could shift it back by 2010. Too late for 08, but 2010 things could shift.
More likely 2012 though.