Every now and then some learned professor will announce as a great discovery something that most common people with common sense have known all along. A recent example was the latest finding of Harvard's Robert Putnam, who gained fame and acclaim several years ago with his book Bowling Alone, which chronicled the decline of civic life in America.

Now he concludes from his studies that the level of trust in communities breaks down when ethnic and cultural diversity increases. Said Dr. Putnam, "[I]n the presence of diversity we hunker down. We act like turtles. The effect of diversity is worse than had been imagined. And it's not just that we don't trust people who are not like us. In diverse communities, we don't trust people who do not look like us."

He went on to observe that immigration-saturated Los Angeles, "the most diverse human habitation in human history," has the lowest level of trust in the U.S. This means specifically that, "[People] don't trust the local mayor; they don't trust the local paper; they don't trust other people; and they don't trust institutions. The only thing there's more of is protest marches and TV watching."

Dr. Putnam's research indeed confirms what most folks already knew. As the old folk saying goes, "Birds of a feather flock together." This is not to say that people can't bridge their differences. One such bridge is assimilation to common American values. And given our existing diversity, we must make the most of it.

So what is the point adding more and more diversity through endless immigration? It clearly saps our strength with growing distrust and division. That should be plain to anyone with common sense. And it should be the logical conclusion of Putnam's research.

But common sense (and logic too) are highly uncommon in places like Harvard where the priests of political correctness (P.C.) enforce worship of Diversity and all the other gods and goddesses of their multi-cult. Maybe Putnam is a true believer, or maybe he just goes along to get along. In any case, after making his observations, he quickly burned incense to Diversity, lest she or her priests be offended.

He proclaimed that immigration is a benefit to "importing" societies like the United States and claimed to have remedies for the ills of diversity. One such proposal had a very ominous tone. Said Putnam, "[Trends] have been constructed, and can be socially reconstructed… we shouldn't say that… [immigrants] should be more like us. We should construct a new us."

The plain meaning of this academic gobbledygook seems to be as follows: Diversity may cause division and distrust, but "social reconstruction" (presumably meaning government power) will force us to swallow our distrust — and our preferences — and like it. Then "we" can construct a new us.

And just who might this royal "we" be? To hazard a guess, it might consist of highly-paid bureaucratic shock troops recruited from places like Harvard. American elites are always telling us that immigration brings enrichment, and for them, in so many ways, it quite often does. Our would-be diversity enforcers know very well that force is the only thing that can hold hyper diversity together, and evidently they want to be the ones who supply the force.

So what does this mean for our traditional American freedoms? The prospects are not encouraging. Take free speech, for example. With diverse views and cultures all about, it will be hard for anyone to say anything significant without offending someone else. In this situation, our diversity managers may decide to scrap the free speech provision of the First Amendment in the name of social peace. That indeed would construct a "new us," tongue-tied, silent and fearful.

Our Founding Fathers were well aware that common sentiments were necessary to ensure the trust necessary to maintain freedom. John Jay in the Federalist Papers hailed America as "one united people… speaking the same language, attached to the same principles of government, very similar in their manners and customs."

As mass immigration makes us less and less "one united people," we Americans should pay no heed at all to the elites' tired mantra, "Diversity is our strength." It's their strength, not ours.