Chris Simcox, founder of the Minuteman Civil Defense Corps, has his sights set on John McCain’s Senate seat.

– UPDATE – Arizona Republicans react to Simcox's bid against McCain at http://www.azcapitoltimes.com/freestory.cfm?ID=11006 

Sen. John McCain will face a challenge from the right in next year's Republican primary, as one of the country's most prominent border hawks will announce his candidacy for Arizona's Senate seat on April 22.

Chris Simcox, who founded the Minuteman Civil Defense Corps, will file campaign paperwork today to formalize his challenge of McCain, who has angered conservative Republicans for his stances on a variety of issues – most prominantly, illegal immigration and border security.

Simcox will represent a stark contrast in Republican ideology compared to that of McCain, said Eric Johnson, a senior advisor to Simcox and former staffer for Don Goldwater's gubernatorial campaign in 2006.

"He is a true, conservative Republican. His platform is what it should be," Johnson said.

Some of McCain's clashes with conservatives in the Republican Party include his sponsoring 2006 effort in Congress to reform American immigration policies and allow a "pathway to citizenship" for millions of immigrants in the country illegally. He also spearheaded campaign finance reform in 2002 and has supported efforts to limit sales of firearms at gun shows.

Johnson said Simcox's proven ability to organize a grassroots campaign will give him an advantage over McCain. And Robert Kiley, a California political consultant who will manage the campaign, said Simcox's national profile will allow him to raise the $10 million to $15 million needed to take on the entrenched senator.

"We don't think there's going to be an issue raising money," Kiley said. "There's a lot of anger out there."

Although Kiley and Johnson touted Simcox's stances on other GOP issues, such as abortion and gun control, they said immigration will play a larger role in the campaign. Simcox will push to secure the border immediately by using the National Guard. But unlike in President Bush's 2006 Operation Jump Start, in which thousands of guardsmen were sent to the border to support the Border Patrol, Simcox wants the soldiers to take an active role in stopping illegal activity and detaining people who are trying to enter the country illegally.

Johnson said the campaign also will target voters who have left the Republican Party in recent years because of dissatisfaction with elected officials whom they believe abandoned the party's principles.

"There are a lot of people who left Republicans and became independent because of McCain," Johnson said.