Jane Norton, a Republican candidate for the U.S. Senate in Colorado, had a hunch that by dinnertime Wednesday, conservative voters across the state would have heard about a federal judge blocking much of Arizona's immigration law.
She had a hunch they would be angry.
So Ms. Norton's campaign ordered up a new round of robocalls, informing voters that Ms. Norton was proud to have been endorsed by one of the immigration law's strongest advocates, Arizona Gov. Jan Brewer. The campaign had already called 80,000 Republican voters. Now, it planned to call 100,000 more, said Josh Penry, Ms. Norton's campaign manager.
The calls to Colorado voters Wednesday night were just one sign that the federal ruling in Arizona is likely to ripple through this heated campaign season.
Republicans quickly denounced both the ruling and the Obama Justice Department for challenging the law in the first place. Some said the ruling would further energize voters who are angry about what they see as federal overreach on health care and other issues.
Rep. John Boozman, the Republican nominee for the U.S. Senate in Arkansas, said he expected the judge's ruling to further rile voters and motivate them to reject Democratic incumbents. "It's a defining issue," Mr. Boozman said. Mr. Boozman takes questions at every town hall, he said, and "this will come up at every one."
Democrats, divided on the issue and running against stiff political headwinds, were unsure how the ruling would play out.
Some called it an unhelpful distraction from the campaigns they have been building around jobs, economic themes and border enforcement. Pat Waak, chairwoman of the Colorado Democratic Party, said candidates can't win in the fall if they aren't talking about jobs and the economy.
"We're not talking about credit-card companies not being able to take advantage of you, or student loans," she said. "We have to be the messengers of what affects your life."