From a 4/16/05 ACLU press release:

The Immigrants' Rights Project of the American Civil Liberties Union today announced that it has sent two national staff members to Arizona to support the Legal Observer Project organized by the ACLU of Arizona.

Since April 1, armed private individuals under the so-called "Minuteman project" have come to Arizona for the purported purpose of spotting and reporting individuals who the Minutemen claim are violating federal immigration law. In fact, there have been growing reports and allegations of abuse of immigrants as a result of the Minutemen’s activities. Increasingly, it appears that private citizens near the Arizona border are engaging in illegal treatment of immigrants...

[...quote similar to the last paragraph from the Director of the ACLU Immigrants’ Right Project...]

[...repurposed quote from the head of the AZ ACLU...]...

Let's ignore the second paragraph (for now) and concentrate on this news.

There are many possible explanations for the national ACLU to send in the heavyweights. They might indeed be intending simply to "assess the situation in Arizona first-hand" as they say.

An alternative explanation is that they might feel that the AZ ACLU is a bit out of hand and needs to be reined in...

See also this unsubstantiated eyewitness report:

The ACLU is getting desperate to get something on the Minutemen and are trying to provoke incidents now. They pushed one of the Minutemen the other night trying to get him to push back. Didn't work. Then last night they walked up and shined a spotlight right in a Minuteman's face from six inches or so away. Didn't work that time either. We immediately report these types of contacts with them to the Sheriff to counter any claims they try to make against us...

Previous ACLU coverage: Who are the real vigilantes?, The ACLU aiding illegal aliens?, and Waiting for a correction from the ACLU...

Regarding the latter, I spoke with a national ACLU spokesman on Friday. He said that they might update the Bryan Barton-related press release "when the time comes", but that they had no specific plans to release an update or correction.