The gist of this argument is that a combination of demographic changes to American society and key socioeconomic developments are making it likely that the future will belong to the Democratic Party. Among the demographic changes is the assertion that groups especially likely to vote Democrat – African Americans, Hispanics, and other minorities – will be a larger slice of the American electorate in the future, while groups more inclined to back the GOP – especially older, heterosexual white people – will be a smaller portion of the voting-age population.

John Judis and Ruy Teixeira published a bestselling book, The Emerging Democratic Majority, in 2002. Judis hailed the continuing validity of their thesis in an Atlantic article published in November 2012. Other authors, such as Democrat pollster Stanley Greenberg and National Review’s chief political correspondent Tim Alberta , have taken up the drumbeat.

Other changes in America include the decline of marriage and especially the entry of more women into the workforce; each of these allegedly works to the advantage of the Democrats. Add to this the entry into the electorate of the Millennial birth cohort – or people born in 1982 or later. These people are reported to be much more likely to identify with or lean toward the Democrats than the Republicans. Contrast them to America’s so-called “Silent Generation,” who are now in their early-to-late 70s, and considerably more inclined to identify with or lean to the GOP.

Voila, so the argument goes, the future looks rosier for the Democrats than for the Republicans.

Before proceeding, let’s acknowledge that the future may belong to the Democratic Party, for the reasons usually given.

Then again, it may not. Here’s why.

The assertion that America’s future looks rosier for Democrats makes several assumptions, at least some of which seem shaky, at best.

One such assumption is that American policies regarding legal immigration, which have played a significant part in the millions who have flooded into in America, some from countries with cultures that are hostile to traditional American culture, will not be changed. Immigration laws have changed in the past, and may again.

Proponents of the Immigration and Naturalization Act of 1965, such as Ted Kennedy, assured Americans that the new policy would not dramatically alter American culture or the ethnic and racial composition of the populace. They were wrong.

Prior to the 1965 Act, most immigrants to the U.S. came from northern Europe and Canada. After 1965, the bulk of immigrants to America came from Asia, Africa, Mexico, Latin America, the Middle East, and Southern or Eastern Europe. In addition, after a 1921 act curtailed immigration to the U.S., the percentage of immigrants among the populace fell to about five in the mid-1960s. As recently as 2014, immigrants made up roughly 13% of the population, or roughly 42 million people.

Moreover, once-upon-a-time, immigrants to America were expected to assimilate to the culture, primarily by learning English. Recently, sizable slices of the immigrant populace have not assimilated. It doesn’t help when the education establishment, K-20, refuses to inculcate U.S. values, holidays, and the English language into children from immigrant homes.

A further alteration of American culture and society is associated with a large influx of illegal immigrants, an influx that began long before Barack Obama was inaugurated in January 2009. Even so, the Obama administration’s refusal to enforce laws against illegal immigrants, along with historic offers of amnesty to illegals, has made a bad situation much worse.

Proponents of a coming Democrat majority assume that the recently arrived legal and illegal immigrants will, sooner or later, vote in overwhelming proportions for Democrats.

There’s a problem, however, with this assumption. Study the history of immigration to America and you learn that, after a generation or two of being here, living conditions change. First-generation immigrants, and especially their progeny, experience upward mobility, and with improved socioeconomic circumstances have come altered voting patterns.

Many of the one-time immigrants from countries like Ireland, Italy, Poland, and Russia, and especially their children and grandchildren, voted for Donald Trump in 2016.

Another part of the argument has it that immigrants’ – especially Hispanics’ – higher birth rates will, sooner or later, cause them to exceed the native-born population. However, we’re already seeing declining birth rates among some Latinas, and there’s good reason to expect this phenomenon to continue.

Now let’s consider gender and voting patterns. As Abby McCloskey notes in the December 5 National Review, during the last 30+ years, women have made up between 50 and 60 percent of the workforce. Women are now the primary breadwinners in 40% of U.S. households

In addition, the decline of marriage means that 25% of women today are single mothers.

Since at least the 1980s, we’ve been hearing about the “gender gap,” with women more likely to back Democrats at the polls than men. In one sense, the presidential election of 2016 reflected this pattern, with a 24-percentage point gap in men’s and women’s respective votes for Trump and Clinton.

However, when race is considered, a different picture emerges. According to exit polls, Trump received the votes of 63% of white men, but he also got the votes of 53% of white women. It was African American women’s votes, and those of Hispanic women and other minority women, that did much to contribute to a record-level gender gap this year.

(Thus far, I haven’t been able to learn about the voting patterns of young, unmarried, and/or working, women, versus those with other attributes.)

Proponents of a future Democrat majority might do well to realize that when it comes to American elections, race trumps (sorry!) class, and maybe even gender.

Moreover, if Republicans, like Trump in 2016, adopt women-friendly policies, such as paid leaves-of-absence after childbirth, and child-care programs, the Left will no longer own women’s issues. Parties have changed policies before, and may do so again.

Finally, there’s the age factor. Proponents of a new Democrat majority tout the Millennials’ role in bringing that about. But, what if, as they age, Millennials follow earlier birth cohorts, and become less supportive of Democrats and more positive toward the GOP?

In the late 1960s, Baby Boomers, who were just coming-of-age, were much more likely to identify with or lean to the Democrats than the GOP. By 2014, which is the last year for which I could find a poll broken down by partisanship and birth cohorts, 47% of Boomers were some kind of Democrat, while 41% aligned with the GOP.

If a birth cohort alleged to lean to the Left when young could become much less so by the time they reached 50 to 68 years of age, should we expect today’s Millennials to be greatly different?

Moreover, according to Deborah Netburn, in the September 8th Los Angeles Times, a new study finds Millennials are more likely to identify as conservatives than were either the Boomers or Gen Xers at the same age.

There are, in short, several reasons to question the prediction that America’s future belongs to the Democrats. One is reminded of what Yogi Berra said about the trouble with making predictions.