“Suicide Squad”

Rated PG-13 (2:10)

*1/2

Opens today

Three “if”s, a “when” and a “but” regarding the new DC Comics movie “Suicide Squad” starring Will Smith, Margot Robbie, Jared Leto and Viola Davis:

IF you were to make a better film than the one writer-director David Ayer has made, you’d still hire Smith. He takes top billing as Deadshot, the world’s most lethal hit man, who is going through some custody issues with his adorable daughter. Older now, his screen presence informed by a relaxed authority, the star’s underplaying is a relief. In this headache of a movie, he provides the aspirin.

IF you could start this headache over from scratch, you’d still want Margot Robbie in the showcase role of Harley Quinn, former staff psychiatrist at Arkham Asylum, tortured into criminal compliance and twisted devotion by the inmate known as The Joker. Robbie is radioactively watchable, swinging her baseball bat this way and that, selling this skeezy male-fantasy nutjob with wide-eyed enthusiasm. In Ayer’s film, Jared Leto plays The Joker with the voice Heath Ledger cooked up back in “The Dark Knight,” and a mouth borrowed from Gangstas Anonymous. He doesn’t get the screen time some of the presold fanboys expected, which is neither here nor there; “Suicide Squad” is saddled with a bigger cast of characters than “Around the World in 80 Days.”

Finally: IF, in that alternate-universe “Suicide Squad,” you needed a steely authority figure who transforms a cadre of hardened psychos and killers into a black-ops unit designed to take on bad guys from various dimensions, then Viola Davis would be your steely authority figure.

So. WHEN that better movie comes along, be it the already announced sequel or the promised Harley Quinn spinoff vehicle, maybe we’ll get somewhere near a good time.

BUT. Meanwhile we have this thing, this garish, overstaffed, overstuffed, blithely sadistic corporate directive disguised as a PG-13 summer movie for all ages. (You’d be pretty stupid to let anyone under 13 see it. Actually, you’d be pretty stupid to let anyone over 13 see it.) It will open big, and if its de facto prequel “Batman v Superman” could make $872 million worldwide, well, anything’s possible and quality has very little to do with it. “Suicide Squad” is a slightly less punishing experience; it’s brighter, at least, and more openly decadent. Its bases are covered: Anyone who plunked money down for director Zack Snyder’s “Batman v Superman” earlier this year (Snyder executive-produced “Suicide Squad” and will be running the DC movie universe for years to come) feels obligated to check in on this next-door-neighbor movie, which includes cameos from Ben Affleck’s Batman, who looks thrilled to be there, let me tell you, along with a pointless glimpse of The Flash and more.

Fanboy reviews of “Suicide Squad” are already out. I love what Jeremy Szal’s Galaxy Blog in Australia had to say. He rilly rilly liked it, calling it “insane” while noting that Ayer “pushes the PG-13 rating to the limit and then some.” (He added: “Someday I’ll actually be able to process US-ian rating systems — or anything the US says or does — through my Aussie brain.”)

In “Suicide Squad,” we have the familiar “Dirty Dozen” setup. A gaggle of surly sociopaths coupled with some “metahumans” on the order of Adewale Akinnuoye-Agbaje as Killer Croc must set aside their basic natures to work together fighting a common enemy. Ayer’s previous films include “End of Watch” and “Fury,” and his own warring instincts as a director — effective melodrama clashing with cheap pulp — made him a pretty good bet for “Suicide Squad.”

But folks, this is a lousy script, blobby like the endlessly beheaded minions of the squad’s chief adversary. It’s not satisfying storytelling; the flashbacks roll in and out, explaining either too much or too little, and the action may be violent but it’s not interesting. At this point in 2016 America, if there’s one thing I could vote out of all movies, permanently, it’s the drooling slow-motion close-up of hundreds of assault weapon bullets bouncing off gorgeously lit pavement.

The people on screen have their moments; my favorite bit comes when Deadshot, riffing, negotiates payment for services, asking that his overseers make sure to “white-people” his daughter into an Ivy League school if her grades aren’t up to snuff. Later, Deadshot refers to the tornadolike doomsday machine being assembled, endlessly, like the world’s dullest GIF, by the evil Enchantress as “a swirling ring of trash.” That’s “Suicide Squad” in a nutshell, or an empty shell casing. It’s projected to make $100 million to $150 million opening weekend. For bad-behavior superantiheroism that hangs together, at least, “Deadpool” is twice the movie.