I have some shocking statistics to report. Between 1952 and 2004, inclusive, there have been 14 presidential elections. The Democrat candidate received at least 50% of the votes in only two of them: 1964 (61.1%) and 1976 (50.1%). During that same period, the Republican candidate received at least 50% of the votes in seven elections: 1952 (55.2%), 1956 (57.4%), 1972 (60.7%), 1980 (50.7%), 1984 (58.8%), 1988 (53.4%), and 2004 (50.7%). Republicans have won nine of the past 14 presidential elections. (Each party won an election with fewer popular votes than the other party: the Democrats in 1960 and the Republicans in 2000.)
Democrats are in trouble. Their coalition may seem large, since it’s composed of many distinct groups (labor unions, abortionists, teachers, trial lawyers, blacks, homosexuals), but in terms of overall appeal, it’s failing. Repeatedly. Embarrassingly. A party that can’t recruit at least half the American people has the wrong principles and policies for this country. Could that be why the intelligentsia has gone berserk? Even the Democrats who won the presidency haven’t done well. John F. Kennedy received only 49.3% of the popular vote in 1960. Bill Clinton never received half the popular vote. His percentages were 43.0 (the lowest for a winning president during this period) and 49.2. By contrast, seven of the nine Republican winners received at least half the popular vote.
It’s a great time to be a Republican and a terrible time to be a Democrat. Unless and until the Democrat party changes its message, without seeming to do so insincerely, it will be powerless. Here, in case you’re wondering, are the Democrat percentages (from Wikipedia):
1952: 44.3
1956: 42.0
1960: 49.3 (elected)
1964: 61.1 (elected)
1968: 42.7
1972: 37.5
1976: 50.1 (elected)
1980: 41.0
1984: 40.6
1988: 45.6
1992: 43.0 (elected)
1996: 49.2 (elected)
2000: 48.4
2004: 48.3
One more thing. You hear talk these days that there’s nothing wrong with the Democrat platform. The problem, Democrats say, is either the personality of the candidate (think Al Gore) or the inability to articulate what the party stands for (think John Kerry). But there have been many different Democrat candidates in the past 14 elections. Have all of them had bad personalities? Have all of them failed to articulate what the party stands for? It’s the platform, stupid. The American people don’t like it.
While the president gets to be in charge by directing policy, Congress still controls the purse strings. Though the Democrats may be taking a beating now because they controlled the purse strings for so long. You are right that they are suffering because they lack a clear platform beyond, I think, "We'll give you more aid/support/incentives!" After years of Democratic control of Congress, most voting Americans realize this is simply, "We'll raise everyone's taxes and give the money to these special interest groups!"
I believe it is this same problem that will come to hurt the Republicans if they should finally get control of both houses of Congress.
Here's a link to someone that's done all the heavily mathematical analysis of who controlled the Presidency and Congress.
Congress Numbers
If I'm reading the raw numbers at the bottom of that page correctly, the Dems held a majority of both houses from 1955 to 1981, and then again from 1987 to 1995 (The Gingrich "Revolution" if I'm not mistaken).
Today, about a third of the electorate is motivate by its evangelical religious outlook. The religious right is the reliable base for the new GOP. This puts the GOP solidly against civil liberty on every political issue where that is at stake, from contraception to Oregon's death with dignity law. To keep winning elections, all the GOP need do is attract a small wedge of people, a sixth of voters, who aren't in the religious right. That gives it a considerable advantage over the Democratic Party, which is much more ideologically diverse and that doesn't possess any sizable and unified base like the religious right.
The question, of course, is why any sane person would ally themselves with the religious right. The answer is that sanity isn't a requirement. That wedge of "other" voters the GOP must attract need not be the same from election to election. They need not be sensible. They need not understand that they are voting against their own liberty. They can be fooled into thinking that a vote for fundamentalism here is somehow a vote against socialism, or even a vote against fundamentalism abroad. More's the pity.