Topeka ? A professor and Kansas politician who helped draft Arizona’s tough new law on immigration says a Justice Department lawsuit against it is unnecessary and troubling.

Kris Kobach, a law professor at the University of Missouri-Kansas City, predicted Tuesday that the lawsuit would fail.

He is consulting with Arizona’s governor as her state defends the law, which requires state and local police to question and possibly arrest illegal immigrants during the enforcement of other laws.

Kobach lives outside Kansas City, Kan., and is running for Kansas secretary of state.

He noted groups such as the American Civil Liberties Union already have challenged the law.

Kobach said the challenge from the Justice Department, announced Tuesday, is designed only to stir up the Obama administration’s political base.