Editor's note: Ruben Navarrette is a CNN contributor and a nationally syndicated columnist with the Washington Post Writers Group. Follow him on Twitter: @rubennavarrette
San Diego, California (CNN) -- Our politics have changed in America -- and, unfortunately, not for the better.
With the Robert Bork hearings of the 1980s and later the Monica Lewinsky affair of the 1990s, we were introduced to the "politics of personal destruction."
Today, we're living with the hangover and learning how destructive it can be when we take our politics personally. We're a nation divided, where people can no longer agree to disagree without becoming downright nasty.
Just ask Stacey Dash, an African-American actress who was attacked on Twitter for abandoning her support for Obama and daring to publicly endorse Mitt Romney for president. The actress, who starred in the movie "Clueless" and the cable TV drama "Single Ladies," tweeted: "Vote for Romney. The only choice for your future. Team Romney...Vote Romney."
The liberal Twitteratti went crazy. One Twitter user wrote about Dash, who is also half Mexican-American, "You're an unemployed black woman endorsing Mitt Romney. You're voting against yourself thrice. You poor beautiful idiot." Another chimed in with: "I guess 'Clueless' star Stacey Dash endorsing Mitt Romney shows that she is indeed clueless."
But the really ugly barbs came from fellow African-Americans who tweeted that Dash was a "jigaboo," "traitor," "house n-----." You get the picture. Many went further, urging Dash to do everyone a favor and "kill urself."
Or ask Buzz Bissinger, a columnist for The Daily Beast who must have felt as if he was trapped in an episode of "Liberals Gone Wild" after announcing that he had -- after the first presidential debate in Denver -- decided to support Mitt Romney for president.
A self-described "lifelong Democrat," Bissinger wrote in a column after the first presidential debate that he could "no longer back a president who no longer acted like he wanted to be president, who offered a vision for the country as original as those college essays you can buy off the Internet, who in front of 70 million viewers acted like he had 90 minutes to kill before going out to dinner with Michelle for their 20th anniversary."
Bissinger was castigated by his wife and friends and liberal readers, who through what the columnist described as "thousands of comments on The Daily Beast website and Twitter and Facebook; writers from national media outlets trying to pick the column apart because they were outraged that one they considered part of the tribe, a journalist and author, would actually turn away from the ingrained liberal leanings of the profession." His takeaway: "Liberals preach tolerance, but 90% are every bit as nasty and vitriolic as the conservatives they rightfully condemn for being nasty and vitriolic."
And ask Cornel West, one of the country's most prominent African Americans, who last year went into the liberal doghouse when he criticized Obama for abandoning African Americans and the working class. West called Obama a "black mascot of Wall Street oligarchs and a black puppet of corporate plutocrats." He won the wrath of the Rev. Al Sharpton, and fellow academic Melissa Harris-Perry responded by slamming West for making a "self-aggrandizing, victimology sermon."
Of course, conservatives also know full well how to level personal attacks. Radio talk show host Rush Limbaugh stepped in it when he demeaned Georgetown University law student Sandra Fluke as a "slut" after she testified before Congress about the importance of requiring univeristy health insurance plans to cover birth control.
Radio talk show host Glenn Beck, who formerly hosted a daily talk show on the Fox News Channel, once said that President Obama was "a racist" who had "exposed himself over and over again as a guy who has a deep-seated hatred for white people or the white culture."
Then there are all those tea party activists, some of which, in combating Obamacare, thought nothing of holding up racist signs depicting the president as an African witch doctor. Naturally.
At the end of the day, labels like "liberal" and "conservative" don't mean much. Human beings are all the same. Some are raised to be tolerant of different points of view, others not so much. The more secure you are in what you believe, the less likely you are to attack someone for believing something else.
Meanwhile, in this country, a lot of people seem to be on the attack. If you oppose the president, his supporters will call you a racist; if you support him, his opponents will call you a socialist. You're either accused of not loving your fellow man or not loving your country.
It's all part of where we've arrived, and how we've changed. We wear our ideologies on our sleeves. We keep our political views, and presidential choices, close to our hearts. And so when they're challenged, we feel personally wounded. So we get angry. These days, if you challenge someone's point of view or disagree with their choice in candidates, it's as if you're directly attacking them.
It used to be that Americans could disagree over politics and still go out and have a drink. Not anymore. Nowadays, if you disagree, one of you isn't just wrong. One of you is a bad person. And who wants to go drinking with a bad person?
Now, almost everything about politics seems less cerebral and more emotional. The business is no longer about compromising with your opponent; it's about conquering him. We don't just disagree; we're out to destroy. We don't settle for half a loaf; it's all or nothing. The goal isn't to find solutions; the objective is simply to win at all costs.
After Tuesday's presidential debate, Obama was criticized by some Republicans for being too combative. But judging from the polls, Democrats are delighted with Obama's aggressive stance, and they want more of the same in the final debate next week.
As for what got us to this point, maybe the politicians are to blame for leading the way, with their negative ads and their tendency to treat every political campaign like a contact sport.
Or maybe it's generational, a result of what happens when baby boomers -- who, since the Vietnam War, have believed their values were superior to everyone else's -- control the government. Or maybe it comes from living in the Internet age in which everyone has an opinion and feels entitled to express it freely and without apology.
Four years ago, with the election of Barack Obama, it looked as if the United States had taken a giant step forward. Now, it looks as if we're going backward.
The opinions expressed in this commentary are solely those of Ruben Navarrette.