The number of "nativist extremist" groups in the United States, exemplified by the Minuteman groups born in Arizona, shrunk dramatically in 2011, the Southern Poverty Law Center says in its annual report.

Their decline coincided with an explosion in the number of anti-government "Patriot" groups, the report says.

The report describes the Patriot movement this way: "Patriot groups define themselves as opposed to the 'New World Order,' engage in groundless conspiracy theorizing, or advocate or adhere to extreme antigovernment doctrines. Listing here does not imply that the groups themselves advocate or engage in violence or other criminal activities, or are racist."

The number of Patriot groups in the country grew from 824 in 2010 to 1,274 in 2011, the SPLC said, calling that the highest number the group has counted since it began in the Clinton Administration. In Arizona, some of the groups listed by the law center as fitting the definition include: Arizona Citizens Militia in Douglas, Southeast Valley Tea Party Patriots in Santan Valley, and the Constitution Party, present in nine counties. (See the whole list here.)

The number of nativist extremist groups dropped by 42 percent from 319 in 2010 to 184 in 2011, the law center reported. The law center describes these groups as dedicated to confronting suspected illegal immigrants face-to-face, either through border-area detentions, demonstrations at day-labor centers or other activities.

They attributed the drop to a splintering of existing groups and the fact that state legislators have taken up the issue, reducing the apparent need for the ground-level activism. Another factor, said Heidi Beirich, head of the center's Intelligence Project, was the migration of some nativist-extremist  leaders to the Patriot movement.

Not everyone accepts the Southern Poverty Law Center as the arbiter of who is an extremist. In 2010, for example, former Arizona Republic reporter Jerry Kammer wrote this detailed critique of the center's decision to label the Federation for American Immigration Reform a "hate group."

Glenn Spencer, founder of the American Patrol group in the Sierra Vista area, is still fighting accusations by the center that he is an anti-immigrant extremist.