Requiring governors of border states to certify that the flow of illegal immigrants has been halted is central to John McCain's immigration plan.
The Republican frontrunner says he will not move forward with earned legalization until certification is complete.
Tagged by some conservatives as "the amnesty guy," McCain has said that enlisting border governors is a necessary step for restoring the public's confidence that immigration is being brought under control.
Appearing on Bill O'Reilly's program in August, McCain pointed to the Democratic governor of his home state of Arizona as key to his proposal.
"If the governor of my state, who happens to be a Democrat, would be forced she would certify that the border is secure it would be secure," said McCain. "And that would give credibility."
"You'd have to have all the border state governors certify it," he added. "I think that would give credibility to our claim in Washington."
While border certification has proved to be a useful talking point for McCain, Arizona's governor has not been consulted by McCain on certification and she said she considers it unworkable.
"The certification issue sounds good," said Janet Napolitano, the governor of Arizona, in an interview with ABCNews.com, "but it is a snapshot, not a sustained presence, and a snapshot could vary greatly within any given state within any given year."
By relying on governors to certify that the border is secure, McCain is shirking responsibility, Napolitano said.
"If you make certification the only criteria for whether you then move into overall immigration reform, what I would be leery of is putting up a process by which you never have to take responsibility for overall immigration reform," she said.
Napolitano has endorsed Democrat Sen. Barack Obama for president.
Asked how certification would work if the governor of Arizona thinks it is nothing more than "a snapshot," McCain ignored the criticism and instead pointed to the ways in which Texas, where he enjoys the endorsement of Gov. Rick Perry, has gotten involved in beefing up border security.
"Look," said McCain, in an interview with ABC News' Ron Claiborne, "if a nation can't secure its borders then a government can't carry out its responsibilities to the people, because that's our first obligation. I believe we can. I obviously believe that once you do that then we have the tamper-proof documents and stuff."
"People want the borders secured first," he continued. "We've got to do that for them, so that we can satisfy their major concern which is national security."
ABC News' Bret Hovell and Talal Al-Khatib contributed to this report.