Geopolitics being what they are today, Madonna might want to reconsider one element of her “Confessions Tour,” which returns to Madison Square Garden tomorrow for two nights. Midway through the show – which is otherwise excellent, even inspiring – a montage of images of world leaders is displayed above the stage. There’s President Bush, President Ahmadinejad, Secretary of State Rice, Kim Jong Il, Secretary of Defense Rumsfeld, Fidel Castro, and everyone’s favorite punching bag, Vice President Cheney.

The montage makes Madonna’s worldview quite clear: The only difference between a Republican and a dictator is a mustache. Right, they’re all the same. This jolting moment of moral equivalency is topped only by Madonna giving the president of the United States the middle finger. It’s all a big dollop of juvenile thinking in the middle of a highly sophisticated show.

Of course, it’s understood that politics and pop stars don’t mix. But it’s especially frustrating when you consider how broad and diverse Madonna’s audience is. Walk past the Garden when her show lets out, and you’ll be hard-pressed to guess who was onstage. The crowd looks like any random sidewalk scene in Manhattan. The Material Girl’s appeal cuts across all demographics: age, race, sex, sexuality, economic status – and fashion sense, too. Why then does she assume that 15,000 diverse individuals all think in lockstep with her politics?

Well, she’s Madonna. She truly – literally- can do whatever she wants. Unlike, say, the Dixie Chicks, this is an artist who doesn’t have to worry about alienating fans; this tour has been selling out around the world. But if you happen to be a fan who disagrees with her, you can only sigh and watch the show. Pop stars will always get the last word. They’re the ones with the microphones, after all. They live to thumb their noses at authority and enjoy a state of perpetual adolescence, even if their fans are of every age.

This was certainly the case on the night I saw the show earlier this month. To my right was a woman in her late 60s, and to my left was a 16-year-old girl whose mother was seated next to her. I’m not sure we all enjoyed the show equally. The grand dame complained about the loudness, and the teenager was taking cell-phone photos (and sending them) the whole time. But Madonna’s magnetism drew us all there equally. Whether it’s her music, her enviably fit body, or her decades-long triumph of the will, she pulls you in. And once you’re there, you take what she gives you, both insipid politics and a dazzling, exhilarating show.

Much has been written about two of this show’s dramatic entrances. To open, Madonna arrives via a disco ball that descends from the Garden’s ceiling. Later, she ascends, Christ-like, on a mirrored cross (while singing). Both were fun to watch, but the best element of the show was neither controversial nor effects-driven. It was pure dance – and sheer joy to watch.

To the strains of a mash-up called “Music Inferno,” Madonna – sporting a white three-piece suit – strutted across a multicolored dance floor. Once there, she drove the crowd wild with an homage to “Saturday Night Fever.” She did all the dance moves – the famous ones, the corny ones, and the ones you completely forgot about. She looked like she was having so much fun that later I bought a copy of “Saturday Night Fever,” watched all the dance scenes, and, yes, tried to do the moves myself. (Watch out, world.)

After the disco portion, she stripped down to a pair of white leggings and a purple and white-striped, off the shoulder shirt that was pitch perfect ’80s. To hits including “Erotica” and “Lucky Star,” she continued to sing and dance in a way that captured her true showmanship. Madonna is a performer who knows her strengths and weaknesses. At 47, she has the endurance of a professional athlete and the flexibility of a yogi, but by the end of this high-energy show, a modest level of fatigue was setting in. To accommodate this – and to keep the crowd’s energy going – she went back to the vault again. This time, she pulled up the pyramid dance formation that was especially popular in ’80s videos. (Think “Thriller” with Michael Jackson at the center and all his ghouls in a triangle behind him.)

Madonna gave this classic setup a disco flair, and it was a deft production move. In a pyramid formation, the dancers are packed tightly together, so the moves can’t be big or flashy; the steps are based on weight shifts, low kicks, sexy poses, and little gestures or arm movements. What makes it a hit is that the dancers are moving in unison – led by the star – and traveling forward.

By this point in the show, Madonna and her backup dancers had been sweating it out onstage for nearly three hours. This choreography allowed them to deliver a huge impact with minimal (relative to the rest of the show) effort. It’s so simple, it’s practically vaudeville: How ’bout a little song and dance?

Not so for the rest of the show, which was much more complex. Video played a major role: One film showed a series of riders falling off horses (as Madonna did a while ago); another showed several stallions cavorting in giant holes on the beach; yet another told stories of three children in crisis, set to the song “Live To Tell.” Equestrian garb, which includes handy, multi-use items like bits, reins, and crops, held sway over the opening of the show. The costuming and choreography created the feeling that the dancers are all both master and beast; Madonna sat on a saddle affixed to a man’s back, but then they all pranced offstage together in a herd. All alone later, she sang “Like a Virgin” while riding a black, carousel-type horse (with a convenient pole) that went around in a circle.

The balance of new and old songs was equitable. “La Isla Bonita” was played in a way that made me wonder why I’ve skipped it all these years. “Hung Up” closed the show on a peppy note. For “I Love New York,” Madonna played the guitar, which has earned her a fair amount of criticism.

Guitar may not be her strong suit, but the fact that she added a new instrument to her repertoire is illustrative of who she is: an artist who has continued to evolve. Love her guitar licks or hate them, at least she’s making music – not talking politics.

July 18 and 19 (Madison Square Garden, 212-307-7171).