Forget about soccer moms and NASCAR dads. The key voting bloc in 2008 is the white working class. According to the new conventional wisdom of American politics, the presidential candidate who can win the support of white working class voters will have the inside track on becoming the next president of the United States.

Moreover, the support of this group is considered especially critical for the Democratic candidates since the white working class was a key component of the electoral coalition forged by Franklin Roosevelt during the New Deal. For Democrats to regain their dominant position in American politics, according to this argument, they must first regain the loyalty of the white working class.

It's an appealing story and one that the Democratic presidential candidates appear to believe. Lately both Hillary Clinton and Barack Obama have been spending lots of time on the campaign trail trying to woo white working class voters by promising to renegotiate trade agreements and bring back good paying blue collar jobs in places like Ohio, Pennsylvania, and Indiana.

There's just one problem with this story. It's not 1936 or 1948 any more. It's 2008 and those good paying blue collar jobs are not coming back. The white working class has been shrinking for decades and it's going to continue shrinking. Not only that, but the white working class voters who remain are more likely to be Republicans than Democrats. Instead of trying to return to their glory days of yesteryear, Democrats could spend their time more productively by cultivating the professional and managerial workers who comprise a growing share of the white electorate and who are more sympathetic to the party's current message.

The white working class has been shrinking as a proportion of the overall white electorate for at least the last fifty years, as the data in Table 1 demonstrate. In the 1950s, manual workers make up 47 percent of the white electorate in the United States while sales and clerical workers made up 21 percent and professional and managerial workers made up 32 percent. By the first decade of the 21st century, however, manual workers made up only 24 percent of the white electorate while sales and clerical workers made up 33 percent and professional and managerial workers made up 43 percent.

Table 1. Occupational Status of White Voters by Decade

Source: NES Cumulative File.

At the same time that the white working class has been shrinking as a proportion of the overall white electorate, white working class voters have been shifting their loyalties from the Democratic Party to the Republican Party. As the evidence displayed in Figure 1 shows, during the 1950s and 1960s, white manual workers identified with the Democratic Party at a much higher rate than either white sales and clerical workers or white professional and managerial workers.

Since the 1960s, however, Democratic identification among both white manual workers and white sales and clerical workers has declined sharply while Democratic identification among white professional and managerial workers has risen. Today, white professional and managerial workers are actually more likely to identify with the Democratic Party than either white manual workers or white clerical and sales workers.

Figure 1. Trend in Democratic Identification among White Voters by Occupational Status

Source: NES Cumulative File.

The reason that white professional and managerial workers are now more likely to identify with the Democratic Party than white clerical and sales or manual workers is that their attitudes are more in line with the party's current message. In the 2004 National Election Study survey, 39 percent of white professional and managerial workers described their political views as liberal and 50 percent took the most strongly pro-choice position on the issue of abortion.

In contrast, only 30 percent of white manual workers and 20 percent of white clerical and sales workers described their political views as liberal and only 35 percent of white manual workers and 37 percent of white clerical and sales workers took the most strongly pro-choice position on abortion.

Table 2. Occupational Status of White Democratic Voters by Decade

Source: NES Cumulative File.

As a result of changes in the class composition of the white electorate and shifting party loyalties among white voters, the class composition of the white Democratic electorate has undergone a dramatic change over the past fifty years.

As the data in Table 2 show, manual workers have gone from 52 percent of white Democratic voters in the 1950s to 23 percent in the first decade of the 21st century while professional and managerial workers have gone from 27 percent of white Democratic voters in the 1950s to 51 percent in the first decade of the 21st century.

Among Democratic voters today, professionals and managers outnumber manual workers by a better than two-to-one margin. Someone should tell Hillary Clinton and Barack Obama about this (and maybe the press, too).