The crowd at the Channelside Bay Plaza theater in Tampa on Monday afternoon was pretty small -- about nine people. But every one of them walked out of the theater converts.

"We have got to get people in to see this," said Lou-Anne Cushman, a Republican convention-goer from Arkansas. Her fellow convention-goers all vowed to drag their friends to it. We should hire buses, said another.

The film was "2016: Obama's America," a sharp, smartly made documentary about Obama that threatens to make "anti-colonialism" the new political buzzword, replacing old favorites like "Alinsky," "neocon" and "Third Way."

It also threatens to send the conservative movement scuttling down the rabbit hole of conspiracism. The film eschews birtherism and Obama-is-a-Muslim claims in favor of an elaborate but ultimately still-crackpot theory that the president is driven by his father's politics to undermine America. It concludes by arguing that Obama is driving up the national debt in a deliberate effort to reduce America's superpower status.

You'll hear more about it soon. The film has taken in $6.2 million at the box office already and has just been given a wide release in more than 1,000 theaters.

It is the brainchild of conservative author Dinesh D'Souza, who co-wrote, co-directed and produced it. He also serves serves as the on-screen host and narrator.

On a technical level, the film is excellent. This is no tiresome collection of talking heads, but a stylish and cleverly conceived narrative investigation into Obama's unusual family history. It uses excerpts from the audio book version of Obama's memoir "Dreams From My Father" to striking effect. We literally hear Obama's voice as it seems to bolster D'Souza's theory.

That theory is that Obama is driven by his father's "anti-colonialism." To vastly oversimplify, this is the left-wing school of thought that the Western world achieved ascendancy by oppressing and exploiting the Third World.

This supposedly explains all of Obama's policies, from his frosty relations with Israel and outreach to Muslim world, to the refusal to intervene in Syria, to the resistance to offshore drilling and the rising national debt.

That the son is influenced by his father is superficially plausible. Though Obama only met his father once at age 10, he did write an entire memoir about his search for identity by trying to understand his absent father.

But anyone who has actually read "Dreams From My Father" will recognize that anti-colonialism is the not the book's theme. Obama's father's politics barely rate a mention in a memoir written well before Obama had settled on his own political career. There would have been no reason to hide any of this if it were important to Obama.

D'Souza also ignores that anti-colonialism is a fairly common part of contemporary liberal thought. It does not say anything unique about Obama that elements of it can be spotted in his speeches or writings. You can spot them in New York Times editorials, too.

Obama's Israel policy, for example, is essentially the same one many liberals have fruitlessly pursued: Show less favoritism to the Jewish state in the hopes of getting concessions from the Arab ones. That it is not working has Obama baffled rather than pleased.

Similarly, Obama is hardly the first Democrat to refuse to make serious cuts to government spending. Are Harry Reid and Nancy Pelosi driven by anti-colonialist ideology they inherited from their Kenyan fathers too? Is Paul Krugman?

D'Souza goes so far as to argue that Obama is not financially supporting his Kenyan half brother George Obama specifically because he rejects anti-colonialism. This bizarre explanation is far from the simplest, and it ignores that George is a grown man whom Barack barely knows, part of a huge extended family.

When D'Souza first put this theory forward in a 2010 book, "The Roots of Obama's Rage," most conservatives rejected it. The film is giving it a second life on the Right. A short preview was shown to cheers at a Tampa Tea Party rally held just before the Republican convention. D'Souza has touted it on several Fox News shows.

Will this help the GOP? I doubt it. This precisely the moment the GOP needs to tighten its argument against Obama's actual policies, not start creating new and implausible theories to discredit his presidency.

Sean Higgins (shiggins@washingtonexaminer.com) is a senior editorial writer for The Washington Examiner. Follow him on Twitter at @seanghiggins.