Well, that was then, and this is now. White working class voters -- or white non-college voters, the exit poll group most closely approximating them -- are now a mainstay of the Republican coalition.
Ronald Brownstein, a clear-sighted and diligent analyst of demographic voting data, provided some useful perspective in his most recent National Journal column. His bottom line is that in order to win this year, Mitt Romney must capture two-thirds of white non-college voters -- about the same percentage that voted for Ronald Reagan in his 1984 landslide re-election.
The reason Romney must do so well is that white non-college voters are a smaller part of the electorate now than they were then. In 1984, they comprised 61 percent of all voters. In 2008, they comprised 39 percent.
The good news for Romney is that Republicans have been running near these levels for some time. In 2008, the white non-college vote went 58 to 40 percent for John McCain. In 2010, the white non-college vote for the House of Representatives was 63 to 33 percent Republican. Current polling shows Obama at about 33 percent among this group.
Another way to look at it is that in 1984, white non-college voters came in 7 percent more Republican than the national average. In 2008 and 2010, they came in 11 to 12 percent more Republican than average.
Such data tends to undercut the theory, first advanced by Ruy Teixeira and John Judis in their 2002 book "The Emerging Democratic Majority," that as minorities and working women became a larger share of the electorate, Democrats could command majorities for years to come.
That was true in some years, like 2006 and 2008, but not in others, like 2009 and 2010. Then it was counterbalanced by heavy Republican margins among white non-college voters.
As a majority group -- 86 percent of voters in 1940 and 61 percent in 1984 -- white non-college voters could not be ignored by either party. Party platforms and candidate rhetoric were aimed at them. A party that failed to win over this group, like the Democrats in 1984, would suffer landslide defeat.
Also, voters who are conscious they are part of a group that accounts for a large majority of the electorate will be open to appeals from both parties. They can be confident that both, over time, will be looking for their votes.
Things operate differently with groups that are self-conscious minorities. One party may antagonize them in search of votes from other groups. Democrats' efforts to woo blacks and liberal college-educated whites turned off the white working class in the 1980s.
Barack Obama seems to be doing the same thing this year. His support of same-sex marriage won't help with non-college whites. Nor will his blocking the Keystone pipeline with all its blue-collar jobs.
Add to the list the contraception mandate being denounced in Catholic churches. And the move to give work permits to something like 1 million illegal immigrants.
In each case, Obama is trying to instill enthusiasm in a core Democratic constituency -- and poking a finger in the eye of the white working class.
Meanwhile, there is evidence that demographics may not work as strongly for Democrats as many predicted.
The Pew Hispanic Center reported in April there has been more reverse migration to Mexico than Mexican migration into the U.S. since 2007, and the Pew Research Center reported Monday that in 2010 there were more mostly high-skill immigrants from Asian than mostly low-skill immigrants from Latin America.
According to exit polls, Latinos made up 9 percent of the electorate in 2008 and 8 percent in 2010. They voted 67 to 31 percent for Obama in 2008 and 60 to 38 percent Democratic for House candidates in 2010.
Obama's support among them seems to be holding up well, but Latino turnout may be low, as it was in California's primary. The virtual halt in Latin immigration makes it unlikely Latinos will double their share of the electorate soon, if ever.
Meantime, there are four times as many white non-college voters leaning Republican by a similar margin. Demographics can work both ways.