When President Barack Obama’s administration sued Arizona over the state’s tough-as-nails immigration law this week, he piled pressure on House Democrats in the state facing a tough battle for reelection in November, analysts say.

OBAMA/The administration on Tuesday argued that the Arizona law, which requires state and local police to investigate the immigration status of anyone who they reasonably suspect is in the country illegally, is unconstitutional and would sap law enforcement resources.

Analysts say the move wrong footed several House Democrats locked in competitive reelection races in the desert border state, where the new immigration law consistently scores solid poll ratings among a broad spectrum of voters.

“It is a proactive act that is effectively blocking something that the voters want,” Rice University political science professor Mark Jones told Reuters. “Any Democrat in a competitive race is not going to like this.”

Those facing potential fallout from the legal challenge are Reps. Ann Kirkpatrick, Harry Mitchell and Gabrielle Giffords, who are all seeking reelection in Arizona congressional districts that already lean Republican.