“The governor understands that immigration is a federal responsibility, and she has made that pretty clear by asking for federal help,” said James W. Ziglar, senior fellow at the Migration Policy Institute and a former commissioner of the Immigration and Naturalization Service.

Of the border fence, Ms. Napolitano famously said: “You show me a 50-foot wall, and I’ll show you a 51-foot ladder.”

Ms. Napolitano has supported the concept of a “virtual fence,” or using surveillance and technology to monitor smugglers.

Her nomination was applauded by business groups who think she’ll support efforts to expand guest-worker programs.

As governor, Ms. Napolitano pushed for so-called comprehensive immigration reform. She has supported a temporary worker program and called for a national employer-verification system.