Watching Donald Trump's joint "60 Minutes" interview with Mike Pence, shot at Trump's home at Trump Tower, I couldn't stop fixating on the awful chairs the candidates were sitting in.

Those tacky, ostentatious, apparently gold-plated, thronelike chairs look like they belong at one of Saddam Hussein's palaces.

Donald Trump has the home-decorating taste of a third-world dictator. This is not a coincidence.

Before he dropped out of the race, and before he reluctantly and painfully endorsed Trump for president, Florida Sen. Marco Rubio observed that Trump is "the most vulgar person to ever aspire to the presidency."

This matters. Trump's vulgarity is a manifestation of his complete lack of self-control — the nonexistence of any voice inside his head that says, "Maybe I shouldn't do that thing. Maybe that will be embarrassing. Maybe people will think I'm a tacky show-off if I do this."

Trump has no idea that discretion is the better part of valor.

It's why he brags about his IQ, his wealth, the size of his penis, and even his humility. (Trump, in Sunday's interview: "I think I am actually humble. I think I'm much more humble than you would understand.") It's why he insulted the physical appearance of Ted Cruz's wife and suggested his father might have helped to kill JFK. It's why he called Mexican immigrants rapists. It's why he hesitated to disavow David Duke, the former grand wizard of the Ku Klux Klan, and said he'd try to be "unpredictable" in his handling of nuclear weapons.

And it's why he bought those hideous chairs.

Trump's vulgarity matters because of what it says about his judgment. Given the way he has been willing to debase himself, the Republican Party, and the country during his campaign, who knows what he might do as president?

But it also matters because it gives other people license to be vulgar — to follow their own worst impulses instead of restraining themselves.

Some manifestations of such vulgarity won't matter too much. If a Trump presidency leads to a surge in ostentatious home decorating, that would be unfortunate, but the Republic wouldn't be threatened.

But Trump's vulgarity also matters for things more serious than furniture.

One really problematic manifestation of Trump-induced vulgarity is one we're already seeing — the open expression of prejudices and hatreds that people have kept quiet about.

Donald Trump. CBS

Trump threatens to normalize crude and crass degradation of women.

He also threatens to make our society ruder and meaner in ways that don't especially relate to race or gender or any other grouping — if a major party presidential nominee goes around calling anyone who stands in his way a "loser," why shouldn't you?

Trump did not invent racism or sexism or crudeness or rudeness. In fact, one of the reasons his candidacy has been as successful as it has is that a lot of voters out there wanted someone who spoke to their racism, or their resentment of women, or their desire to lash out at whatever "haters and losers" they thought had wronged them.

Trump did not invent these attitudes, but he did give people permission to stop hiding them. That's scary because one thing that holds us together as a society is our self-suppression of our prejudices and our hatreds. When it comes to suppressing one's worst attitudes, faking it is a virtue.

I have sometimes gotten pushback when I have, on Twitter, described Trump's racist and sexist comments as "tacky." This word may sound like it minimizes how bad Trump is, since it's a word we also use to describe tasteless clothes and ugly chairs. Shouldn't we call Trump offensive, scary, divisive, dangerous?

Of course Trump is all of those things, but it is important to also say that he is tacky, and that his bigotry is tacky, because often the only thing that stops people from behaving like Trump is their sense that doing so would be tacky, and that tackiness is to be avoided.

That is, people often stop themselves from saying bigoted things not because they have goodness in their hearts, but because they don't want to be looked at askance.

I worry about this especially as a gay man. Let's be real: A lot of people have a visceral, gut-level discomfort with homosexuality. Over the last few decades, gays have come to be treated better in part because many people's gut feelings have changed. But partly, they have changed because people have decided, consciously, that their gut feelings about gay people are wrong, and that they should resist the temptation to express those feelings.

And partly, expressed attitudes about gays have changed because people think their anti-gay feelings have become socially unacceptable, and so they should stifle themselves and not express them, even if they still think those feelings are right.

Of course, what I most want is for people to not have a problem with me as a gay man, but I'll count any of the shifts described above as positive. They're especially positive because a generation of parents suppressing their gut-level dislike of gays have managed to raise another generation that, by and large, is getting to adulthood without those negative feelings at all.

On acceptance of gays, lots of Americans have been faking it until they make it — and I suspect the phenomenon is similar for the suppression and reduction of all sorts of prejudices and bigotries.

Donald Trump threatens to interfere with this process by telling Americans we don't have to suppress our basest instincts — that it is OK to let our vulgar flags fly.

If his vulgar ideas take hold, the terrible chairs that would show up in strivers' living rooms across America would be the least of our problems — the big problem is that the people sitting in those chairs would feel free to express vulgar bigotries.