The "passion gap" over gun restrictions may be narrowing, but it has certainly not closed.

I reported on this gap — those favoring gun rights being much more passionate than those favoring gun restrictions — last year in this piece. Essentially, I argued, the public favors more gun restrictions than are enacted, largely because pro-gun-rights activists are much more energized and organized than those who support more restrictions.

The Dec. 14 massacre of school children in Newtown, Conn. energized those who would impose more restrictions on some guns and components, such as so-called "assault weapons" and high-capacity magazines. A Pew Research Center poll after the Newtown massacre was one of several that showed increased public support for gun control measures.

That growth has been reflected in the support for Arizonans for Gun Safety, which has grown steadily for the last year or two but spiked since the Newtown mass shooting, said group president Hildy Saizow.

"I think this is different. It looks and feels different," Saizow said. "We haven’t really had a situation where we ‘ve had this many mass shootings in such a short period of time, as well as these young, young children involved in the mass shootings."

However, for a group like hers, that galvanization means a tiny group is simply becoming less tiny. The group's mailing list has grown from 200 to 850.

Contrast that with the Arizona Citizens Defense League, which has been one of the main forces behind bills in Arizona's Legislature that would expand gun rights. It started with four co-founders in 2005 and now has about 7,300 members, spokesman Charles Heller said. It's been adding about 1,000 members every six months, he said.

"We have a magnificent machine in Arizona," Heller said. 

Both groups expect to be fighting defensive battles this year, against bills introduced by their opponents' allies in the Legislature. Saizow thinks the trend is in her group's favor.

"The last two years, the extremist bills haven’t been put into law. I think the extremist agenda has hit a wall here," she said, referring for example, to bills that would have made it legal to carry concealed weapons on college campuses.

Heller said his group expects to fight off what he called "standard nuttery — ban the device andward off the evil talisman."

A similar struggle will also be gong on in Congress. Sen. Dianne Feinstein announced after the Newtown massacre that she would introduce a bill to impose a new assault-weapons ban, and Tucson's two congressmen were among many expressing support for the idea. However, gun-rights groups are mobilizing their supporters to fight the bill.