LAS VEGAS (AP) — Defiant Republican governors are demanding that the Obama administration suspend plans to resettle thousands of Syrian refugees in their states.

The state leaders charged Wednesday that screening challenges make it all but impossible to identify terrorists among those seeking refuge in the United States so soon after deadly attacks in Paris.

Governors from New Mexico to Michigan pleaded with the president to suspend the refugee program — at least temporarily. Republican governors from Texas and Indiana claimed the legal authority to block the federal resettlement efforts unilaterally.

Despite the tough talk, it may not be that easy.

The Refugee Act of 1980 dictates that refugee resettlement within the United States is managed by the federal government. Individual states do not have the legal authority to block refugee placement.