During his time at Arizona State University, Amster was engaged in a number of well-reported and controversial activist endeavors. He led an effort to overturn an ordinance making it a criminal offense to sit on the local sidewalks, arguing the case before a
federal judge and winning an
injunction against enforcement of the law before it was overturned on appeal. Amster organized "
sit-in" demonstrations against the ordinance, which he argued was aimed primarily at the local homeless population. He also helped to spearhead a successful campaign to preserve one of the last remaining open spaces in downtown
Tempe, Arizona. These efforts resulted in a number of articles, editorials, and interviews about his work – including an extensive
Phoenix New Times portrayal in 2000 and also formed the basis for his doctoral dissertation, which subsequently yielded two books on these themes of
public space and
nonviolence. He was featured in Jeff Ferrell's 2001 book
Tearing Down the Streets: Adventures in Urban Anarchy as a practitioner of nonviolent "anarchist direct action" in the effort to "reclaim public space" in downtown Tempe. Amster, a critic of
military adventurism and an
interventionist foreign policy, has been a vocal opponent of the wars in
Iraq and
Afghanistan since their inception; he was part of a local group engaging in
civil disobedience when the
Iraq War began in March 2003, resulting in a trial later that year during which he acted as lead attorney for the group as they invoked a "
necessity defense" in light of their assertion of the war's illegality under
international law. He engaged in
grassroots relief efforts in
New Orleans and the
Gulf Coast following
Hurricane Katrina in 2005, working with
Food Not Bombs and local collectives in the region. Amster has worked with the
Catalyst Infoshop in
Prescott, Arizona, and was part of a group that supported founder
Bill Rodgers during the course of his arrest, prosecution, and eventual death in jail in December 2005 on charges of
ecoterrorist arson attacks. From 2005 to 2007, Amster was part of a
legal observer initiative on the U.S.-Mexico border that monitored the activities of the
Minuteman Project. In 2008, he received an award for Entertainment Program of the Year for hosting and producing a local television program on politics and culture, ''The Artist's Mind''. Following the passage of Arizona's immigration law,
SB 1070 in April 2010, Amster began to refocus his activism. He authored a series of articles on Arizona, and helped spearhead an initiative that brought together more than a dozen academic and professional associations in issuing a joint statement condemning
SB 1070 and related state policies. After a federal judge blocked parts of
SB 1070 from taking effect in July 2010, Amster's editorial on the ruling was excerpted by
USA Today. His editorial argued that "there is a sense of vindication and relief on the part of many who have been working for justice in regard to immigration issues." In the ensuing months, he continued to write on related topics. ==Writing and scholarship==