SAN DIEGO — Joe Biden's weak and pathetic relationship with Latinos is all about geography.

As a native of Pennsylvania, a lifelong resident of Delaware, and a creature of Washington D.C., the presumptive Democratic nominee has spent his life in places where you don't find many Latinos.

Let's clarify terms. When I say "Latinos," I'm talking primarily about Mexicans and Mexican Americans who make up about two-thirds of the 57 million people in the United States who claim Latino ancestry. These people represent the Latino "swing vote."

Here's how we divide the empanada. Republicans tend to do well with anti-socialist Cuban Americans, Venezuelans and Colombians. Democrats have a lock on Puerto Ricans, Dominicans, and Central Americans. But Mexicans and Mexican Americans are up for grabs. Basically conservative, we're registered Democrats who will vote for middle-of-the-road Republicans without changing party registration.

Biden probably doesn't know any of this. His peeps are working-class whites in the Rust Belt, the so-called "lunch bucket" union Democrats who think all Latinos got here last week with the intent of taking their jobs and moving factories to Mexico. After decades of commuting on Amtrak to the nation's capital down the Acela corridor to serve in the Senate, Biden expanded his crayon box to include one more color: black. Suddenly, in addition to working-class whites, he was also listening to African Americans, many of whom worry that Latinos push them out of their neighborhoods and take attention away from their plight.

The hard truth is that the 77-year-old former vice president has never spent much time around, or been the least bit curious about, the ethnic group that — in his lifetime — surpassed African Americans to become America's largest minority. That was a huge story when it happened, in 2003, and Biden probably spent that day reading the sports page.

Like a long list of other Democratic presidential nominees — Walter Mondale, Michael Dukakis, Bill Clinton, Al Gore, John Kerry, Barack Obama, Hillary Clinton. et al — Biden treats Latinos as an afterthought.

Now, according to the polls and the tea leaves, Latinos are poised to return the favor.

Younger Latinos are even less excited about Biden. A lot of Latino millennials, between the ages of 25 and 39, were bullish on Bernie Sanders in the Democrat primary. And, they're showing no interest in dutifully shifting their support to Biden in the general election.

Of course, many Latinos hate Donald Trump. At this point, who doesn't? That's not enough. In politics, indifference can be lethal. It doesn't get you to the polls. It keeps you home on the couch.

Biden can't get any love from Latinos, because he's never given any love in return. A recent article in Politico details the disarray in the Biden campaign's virtually non-existent Latino outreach efforts.

What did the Democrat expect? That, he could just show up after decades of neglect — holding a sign that reads: "Vote for me, amigos. I'm not Donald Trump" — and Latino voters would stampede to the polls to support him?

In Biden's case, the story gets worse. It's not just that he has spent his entire career in politics ignoring Latinos and taking their support for granted. Mondale, Dukakis, and Kerry did that, too. That's benign neglect.

Biden went further. Many of his attacks on Latinos, and other people of color, were malignant. It wasn't personal. Just business. In politics, Biden made his name in the protection business. He protected white people from black and brown people who didn't know their place.

By authoring the notorious 1994 crime bill, Biden became the father of mass incarceration. And many of those who were incarcerated were Latino. Later, as vice president, Biden aided and abetted the nation's first black president as he went about separating countless families, putting refugee kids in cages, and deporting nearly three million people — most of them Latino.

You think Mexicans will forget that? Por favor. We haven't even forgotten that California used to be under different management.

With Latinos, Biden has no shot. He'll bleed votes in the Southwest, and he could surrender as much as 33% of Latinos to Trump.

In fact, don't be surprised if the most anti-Latino president in the last half century starts appearing before Latino crowds holding a sign that reads: "Vote for me, amigos. I'm not Joe Biden."

Ruben Navarrette can be reached at ruben@wctrib.com.