And I'll point out that 1964 was a benchmark year. It was the last time that we saw a classic liberal party in this country, and it won a landslide victory. After that, it completely redefined itself by adopting homosexual rights, the right to murder unborn children, the disarming of law-abiding citizens so that they can become defenseless victims of violent crime, and affirmative action quotas as the cornerstones of their party platform.
Since then, out of nine elections the conservative party has won three genuine landslides (1972, 1980 and 1984). The now-radical liberal party has won only three, and two of them were plurality victories (less than 50% was still good enough for a win, thanks to Perot).
I choose 1964 as the benchmark because the vast majority of Americans never voted in an election prior to 1964. This is really the modern era of American politics. So much has happened since 1964 that distinguishes this era from every election before it.
I was a history major way back when, and most survey courses chose the end of WWII as the start of post-modern American history. Starting at 1964 would exclude the Marshall plan which defined much of our modern foreign policy, as well as the beginnings of the Vietnam War and the civil rights movement. So if you wanted to start at 1945, which excludes FDR, we have 28 years of Democrats in the White House and 28 years of Republicans in the White House. That's about as even as you can get. Of course, Bush will make it 29-28 at the end of this year, barring a whole slew of executive assassinations. But if one Supreme Court vote had went the other way, we might very well be talking about Gore making it 29-28. =) I chose 1932 because that's where you have the real start of the liberal Democratic party and the conservative Republican party IMO. Republicans are still trying to undo FDR's New Deal to this day.