Two House subcommittees will be holding a joint hearing tomorrow (judiciary.house.gov/hearings/hear_090402.html) in an attempt to block the 287g program that allows local police to cooperate with the Department of Homeland Security to locate illegal aliens. The most famous use of 287(g) involves Sheriff Joe Arpaio; he isn't scheduled to testify, but two of those who are will be opposing his efforts specifically.

In advance of the hearing, today the American Civil Liberties Union - a group that's directly collaborating with the Mexican government - called on the Obama administration to end the program (aclu.org/immigrants/gen/39244prs20090401.html, link):

The ACLU is calling for an end to all partnerships under the 287(g) program, which trains and allows local and county police forces to enforce immigration statutes. The group also is pushing for a federal law that would require police to document all contacts with the public to better track racial and ethnic profiling.

There's a press release and some information on those testifying at [1]. The co-chairs are Zoe Lofgren and Jerrold Nadler. One person testifying against it is Mesa police chief George Gascon (link). Another appeared at a Casa de Maryland rally, but whether he's linked to that group isn't known (link). Another is Deborah Weissman of the University of North Carolina at Chapel Hill School of Law; she collaborated with the ACLU of NC to produce an anti-287g report (link). From the American side, one of those testifying for the program is described here.

[1] blogs.phoenixnewtimes.com/bastard/2009/04/house_judiciarys_witness_list.php