Boxer — whose relatively mild reaction to Obama’s surprise announcement Friday was in contrast to heated rebukes by environmental groups — said she will stand by those groups in any litigation to force the administration to issue a final ozone rule that goes beyond what was enacted by President George W. Bush.

Environmental groups charged that Obama made a political calculus by punting on a rule that was a particular target of critics who charge his regulatory agenda has hurt the economy and jobs.

Boxer didn’t quite go there. “I’m not making any charge. I’m just saying I disagree, strongly, with their decision,” she told reporters Tuesday. She added, “And I hope they’ll be sued in court and I hope the court can stand by the Clean Air Act.”