Sen. John McCain is a principled politician when it comes to immigration.

His principle is politics.

When it's politically beneficial, McCain is a sharp-taloned border-security raptor, insisting that above all we must "complete the danged fence."

This usually occurs during Republican primaries.

And when it's politically beneficial, he quickly changes into a common-sense immigration dove - to use his conservative opponents' term, he becomes McAmnesty.

He returned to that role on Monday as one of the eight senators making another stab at comprehensive immigration reform. They argued this effort will be different from previous, failed ones.

The difference, as McCain freely acknowledged Monday, is politics. Asked by CNN's Wolf Blitzer whether politics is the reason more Republicans are embracing immigration reform now, McCain responded:

"Well, I'm not sure if it's 'politics,' but it certainly is a realization that if we continue to polarize the Latino/Hispanic vote, that the demographics indicate that our chances for being in the majority are minimal."

In other words, Yes, Wolf, it's politics.

The stance McCain took Monday seems to be his default position, the one he takes when he's not in a primary race. In 2003, he expressed his support for a new "amnesty," before that concept was banned in GOP circles.

Two years later, he, U.S. Sen. Edward Kennedy and others authored the Secure America and Orderly Immigration Act. If you've read about the new framework for immigration reform announced Monday, you'll find the 2005 version familiar.

It included, among other things, a guest-worker program; electronic verification of an applicant's legal status for employers; and a path to legalization for those here illegally, requiring fines and background checks.

After that bill failed, McCain went through the same exercise in 2007, again teaming with Kennedy to introduce an immigration-reform bill. Again the bill died in Congress, largely due to conservative opposition.

Then, in 2008, McCain was running hard for the Republican presidential nomination and needed conservatives' votes. His tone changed abruptly.

Los Angeles Times reporter Janet Hook asked McCain, during a January 2008 debate at the Ronald Reagan Presidential Library, if, given the chance, he would vote for the immigration-reform bill he had authored months before.

"No, I would not, because we know what the situation is today. The people want the border secured first," he responded.

And McCain wanted the nomination.

Then came 2010, Arizona's peak year for immigration hysteria, when SB 1070 was signed into law. McCain faced a primary challenge from the right by former U.S. Rep. J.D. Hayworth.

He put the politics-principle back to work.

In Tucson, McCain billboards screamed "Secure the Border" and the senator introduced a little-known sheriff with a bright smile to vouch for him on border security.

In a campaign ad that gained instant infamy, McCain walked along the border fence near Nogales with Pinal County Sheriff Paul Babeu, who listed good border-security measures.

"And complete the danged fence," McCain added.

That, even though in 2006 he had told a Milwaukee crowd he considered building a border fence the "least effective" immigration measure, adding, according to Vanity Fair magazine, "I'll build the goddamned fence if they want it."

Maybe this time he'll actually get immigration reform done. We'd better hope it happens before his next primary.

Contact columnist Tim Steller at 807-8427 or