Geraldo Rivera -- who has gone from TV showman to defender of la raza with his new book subtitled "Why Americans Fear Hispanics in the U.S." -- warmed up a Latino luncheon crowd the other day with the one joke he says he knows in Spanish.

"The only difference among us Hispanics is the color of our beans," he said in Spanish, to appreciative chuckles. "We're all in this together."

Several hours later, the scene shifted to a Latino comedy night at the Warner Theatre, where comedian and writer Rick Najera was onstage channeling his fictional cousin Buford Gomez Najera, a "redneck Mexican Border Patrol agent."

"Not all Latinos are Mexican," the Buford character explained, to loud applause and cries of "thank you" from the predominantly Latino audience. "There are different kinds of Mexicans -- Puerto Rican Mexicans, Dominican Mexicans . . . Puerto Ricans, you got to remember, they are legal Mexicans!"

So which is it? Are Latinos all the same or all different?

Actually, they're both, depending on who's asking and who's listening.

What Latinos like to tell themselves is how much they have in common -- even as they laugh at their differences. What Latinos like others to notice about them is how diverse they are -- and they consider it politically incorrect if not downright hostile for outsiders to lump them all together.

This paradox was on display this week as another Hispanic Heritage Month rolls around. The shifting nature of Latino identity matters more and more as, with increasing desperation, everyone from would-be presidents to media czars and capitalist kings beseech Hispanics for votes, dollars and devotion.

The Congressional Hispanic Caucus Institute and the National Hispanic Foundation for the Arts drew a couple thousand politicos, activists, lobbyists, celebrities and corporate sponsors to a series of seminars and celebrations around town this week -- capped by the Caucus Institute's gala last night at the Washington Convention Center, where Sen. Barack Obama gave a speech. Sen. John McCain had been invited but did not attend.

The caucus's theme was "The Power to Make the Difference," which is the fashionable way to think about Latinos these days -- the supposedly no-longer-sleeping electoral giant that might decide the presidential election; the nearly-trillion-dollar market that is helping salsa topple ketchup in the American kitchen.

But between the lines and around the edges of all the pontificating, venting, rallying, joking and posing, what the conversations really were about was: Who are we?

Are we English speakers or Spanish speakers? Bilingual? Foreign- or native-born?

How much solidarity do we have across class lines, across differences in immigration status, citizenship, home country? Are we Democrats or Republicans? Are we even voters in the first place?

Rivera suggested that even one's position on immigration reform is a matter of identity and ethnic solidarity: "Any Hispanic, any Latino, any Spanish person who votes for a Republican or a Democrat who is against sensible compassionate immigration reform is an Uncle Tom. They have a kind of self-loathing that is unforgivable."

That drew big applause from the few hundred at lunch. Did anyone disagree? How about those vanquished Latinos in Miami who backed Mitt Romney?

Comedian Willie Barcena didn't disagree, exactly, during his act at the Warner. He just sounded a note of impatience with any insinuation that Latinos, or anybody else, are victims in this country:

"I hate when I hear some Latinos and some blacks talk about 'the white man's keeping me down.' . . . I have yet to see that white guy in front of any of my buddies' houses: 'Hello, Ramon, my name's Todd, I'm the white guy here to keep you down.' "

Applause, laughs.

"By the same token, I hate when I hear some white people going on about 'those illegal aliens taking my job.' . . . Let me tell you something: If a guy gets here from another country, can't read, can't write, can't speak the language, has no technological skills and takes your job? You're a [expletive]."

Barcena adds:

"If you're not successful in this country it's because you're not trying, man, that's all it is."

* * *

Isn't language a proxy for identity?

For all the hand-wringing among English-firsters over the supposed menace of Spanish to American cohesiveness, a young all-English cable network called SíTV looks for its Latino audience on the premise that most under-30 Latinos and nearly all U.S.-born Latinos are bilingual or favor English.

And yet, there's the ever-expanding reach of Univision -- king of the Spanish-language networks, along with Telemundo and Azteca America.

"We speak to these people in the language of their heart," says Joe Uva, chief executive officer of Univision.

The two media models aren't mutually exclusive. SíTV co-founder Jeff Valdez says about 25 percent of the Latino audience prefers Spanish, about 25 percent prefers English, and about 50 percent is bilingual. That means there's the same-size slice of pie -- 75 percent -- available for English and Spanish outlets.

Spanish is hip, and so is English.

"I went to a reggaeton concert recently," says Najera. "The music was in Spanish, the conversations were in English. That's common."

Valdez offers the example of his own household. He grew up speaking English, and his Spanish is not the best. When he speaks Spanish to his sons, 6 and 9, they scoff and tell him to speak English. When his wife, born in Mexico City, addresses the boys in Spanish, they answer in English without complaint. When their Spanish-only housekeeper speaks, they answer in Spanish.

Meanwhile, the boys go to school in Beverly Hills, immersed in American pop culture.

"Their two favorite actresses are Selena Gomez, from 'Wizards of Waverly Place' on Disney, and Demi Lovato," Valdez says. "They don't know why they like Selena and Demi more than Hannah Montana. There's an identification, there's a connection that they're subconsciously unaware of, because there's a validating effect."

* * *

Humor break, from the Warner, during the annual "Reyes of Comedy" night, sponsored by Wal-Mart.

Comedian Bill Santiago: "Even if we deported all the illegals now, it's too late. Cinco de Mayo is now an official American holiday. As a Puerto Rican, I don't celebrate it, but as an American, I have to. It's on the calendar I bought at Wal-Mart."

* * *

What do Puerto Ricans, who are born U.S. citizens, have in common with illegal immigrants seeking a path to citizenship?

Rep. Luis V. Gutierrez (D-Ill.), the son of Puerto Ricans and a champion of immigration reform, raised the question at another midday heritage feast this week.

He recalled that when his parents arrived in Chicago, there were only certain neighborhoods where they could live, and schoolteachers didn't think their son was worth teaching. Back in the 1950s, there was no one to stand up for them.

"I'll be damned if we don't stand up today for those that don't have a voice," Gutierrez said.

One day Gutierrez was back in his district and he saw a Latino wearing jeans, a Western shirt, a jacket with fringe, a big belt buckle, cowboy boots, cowboy hat.

"¡Orale!" the constituent called out to the congressman, using a common friendly exhortation favored by Mexicans. "Your Spanish has improved since you've been in Congress."

Gutierrez appreciated the compliment, because, in fact, he had been practicing.

The man added, "Your Spanish has improved -- because you are speaking more and more like a Mexican!"

The Puerto Rican was taken aback. Then he realized it was the greatest salute the Mexican could have given him: They were different, and yet the same.