Captain America: Civil War is overstuffed and not quite believable in its central concept. It’s also the best Avengers movie since the first one.

It does right what the first one does, on steroids. It was a small cinematic miracle in the The Avengers that gave all the characters (and the stars playing them) enough time to round out their identities and superpowers onscreen. It also contained a powerful message about the dynamics of disunity and the power of overcoming those dynamics. So does this film.

Captain America: Civil War packs a great many additional characters into the plot, almost enough to capsize the entire enterprise. But with a strong central grouping of key characters followed by the gradual introduction of other characters—some familiar and some new—the film manages to feature a large variety of superheroes that gives each his/her moment to shine, and somehow figures out a way to fold them into the plot without awkwardly shoehorning them in.

The central conflict, which nearly everyone knows by now, is around the UN control of the Avengers, who have acquired the reputation of dangerous vigilantes who, without proper oversight, are a law unto themselves, and a group that causes just too much collateral damage while saving the world. The two key leaders of the sides are Captain America (Chris Evans) and Iron Man (Robert Downey, Jr.). The ultimate division of the two groups around the issue is presented logically, but almost comes up as more of a writers’ scenario (“Let’s get them fighting each other like we did in the first film, but more around an issue and less on personalities…”) than an organic development. But only a small suspension of disbelief is necessary, and the arguments are still clear and cogent.

Without going into unnecessary detail on how the groups manage to square off, the film presents scenarios and arguments that can be read in any number of ways. So the film becomes a possible metaphor for:

• Our current election season
• America’s role in the world and its perception by other countries
• Freedom vs. security
• What it means to be a friend
• The dangers of globalism, especially in the political realm
• The naiveté and occasional useless of political leaders
• And much more

In all these issues, always resting under the narrative and personalities, this superhero film is one of the most thoughtful and stimulating films of the year, addressing or at least stirring up issues that more deliberately provocative dramatic films or documentaries tend to overstate or contort. And all this from a summer superhero blockbuster.

As in most of the Marvel films, the acting is top-notch throughout. The casting of talented actors who don’t phone in their performances is one of the strengths of current superhero films, and we only have a go back a few decades to see how far we’ve come.

One particular strength of the film is the pace and cutting of the action scenes, some of the best of the genre. (Pay attention, Mr. Nolan—plenty to learn here). The action scenes are energetic, not confusing, fast-paced but clear in action, and contain intelligent and not overdone sound editing that enhances and doesn’t distract. Instead of being set pieces that pull apart from the rest of the film, they fit snugly into the narrative and feel of the rest of the film. (Mr. Snyder—plenty to learn here.)

One clear goal—and success—of the first Avengers film was to find a place for all these disparate heroes. The goal is the same in this film, but adds another marketing goal of introducing, or reintroducing, others heroes of the Marvel universe to continue some success, bring in a newbie, or jumpstart a reboot. The most successful introduction is Black Panther (Chadwick Boseman), who is brought in gradually and logically, and then fit neatly into the plot. Ant-Man (Paul Rudd) brings a welcome comic presence, but is rather forced in unnaturally and unconvincingly, though the writers have worked him into the plot as well. The clear reboot intentions are around the new Spider-Man (Tom Holland), who is brought in late, but who is given a strong presence, a real place in the plot, and a chance to be funny and juvenile in a way that adds delight to the fight scenes.

The journey in some films from principle to “this time it’s personal” can be groan-inducing. Here, the writers manage to do it with our two central characters that are pitted against one another—Captain America and Iron Man—in a way that makes sense. The main argument about oversight eventually is complicated by a plot revelation that actually means something to the central ideological conflict, and by the time we get to the last major fight scene, the film has found a way to focus the final tensions between these two characters in a way that works.

Other thoughts:

• Any film that features Marisa Tomei has automatically improved itself. If she is the new Aunt May to Holland’s Spider-Man, this is going to be a stronger reboot than it might have seemed.
• Elizabeth Olsen still doesn’t seem to have found her character, Scarlet Witch, in the same way everyone else has found theirs.
• We miss The Hulk, Loki, and Thor.
• Daniel Bruhl as the “bad guy” is neither small and sniveling enough in the Peter Lorre mold nor large and authoritative enough in the Loki-Darth Vader mold to have his character work completely. A fine actor, he’s just not exuding the right stuff here.
• The in-jokes are plenty and funny. “Help me, Wanda”—seriously?

The film starts off rather slowly and allows the people and ideas to sink in before moving into the central conflict. The film has some of the coolness of Captain America: The Winter Soldier without that film’s paranoid detachment, and combines that with clear struggles and understandable actions (and action sequences). Once the grosses begin to recede and the superhero nerds (not a term of derision) have moved on, expect that this film will receive more attention and analysis from the more serious critics and thinkers who will discover, some surprisingly, the depth and complexity of the film and its themes.