In Arizona, the potential threat to Republican Gov. Jan Brewer's re-election bid from her party's right wing was scarcely noted outside her state until she signed the new immigration law.
Brewer initially didn't say whether she would sign the legislation. But she had already angered many conservative voters by pushing a sales tax increase. Republicans planning to contest her for the gubernatorial nomination practically dared her to veto the immigration bill.
"She really did need to sign this immigration bill into law" to save her re-election hopes, said Fred Solop, chairman of political science at Northern Arizona University.
The latest challenge to Brewer may be announced today by none other than Maricopa County Sheriff Joe Arpaio, who has spent the past few days trumpeting his latest roundups of suspected illegal immigrants.