Aside from the sections where he lit into John McCain, the part of Barack Obama's speech tonight that seemed to garner the most enthusiastic response from the Invesco crowd was his recitation of common-ground areas on the most hot-button, divisive cultural issues in America: God (meaning abortion), guns, and gays.

The "three G's" were used to rally the Republican faithful against John Kerry in '04 and the GOP has shown every indication of trying to use them as a wedge issue again against Obama. And so he directly addressed abortion, gun rights, and gay marriage, and I bet that the order he used was no coincidence.

We may not agree on abortion, but surely we can agree on reducing the number of unwanted pregnancies in this country.  The reality of gun ownership may be different for hunters in rural Ohio than for those plagued by gang-violence in Cleveland, but don't tell me we can't uphold the Second Amendment while keeping AK-47s out of the hands of criminals.  I know there are differences on same-sex marriage, but surely we can agree that our gay and lesbian brothers and sisters deserve to visit the person they love in the hospital and to live lives free of discrimination.

With this framing, a call to a recognition of shared values, pragmatic gun laws, and empathy for gay Americans, Obama put McCain and his party in a box. On these key cultural issues, he presents himself as speaking for the broad middle of the country. Who does the GOP represent?

Could John McCain pull off a similar trick next week? If reports of Karl Rove's efforts to head off the v.p. selection of Joe Lieberman are any indication, then I doubt it. If McCain is unwilling to buck the right wing of his party, it seems unlikely that he will go onstage next week and broaden the Republican argument. But if he won't do that, he might not broaden the party's coalition either.

Update: I initially neglected to mention immigration, the fourth hot-button issue Obama mentioned in this section of the speech--and for which he also spoke in favor of an empathetic middle ground: "Passions fly on immigration, but I don't know anyone who benefits when a mother is separated from her infant child or an employer undercuts American wages by hiring illegal workers."

--Ben Wasserstein