This story hasn’t gotten much traction in the mainstream media, but Texas Sen. John Cornyn has been on it all week: Russian submarine activity in the Gulf of Mexico.

After receiving no satisfaction to earlier comments to the media, Cornyn wrote a letter today to Admiral Jonathan Greenert, the Pentagon’s Chief of Naval Operations, demanding answers.

“The submarine patrol, taken together with the air incursions, seems to represent a more aggressive and destabilizing Russian military stance that could pose risks to our national security,” Cornyn wrote. “This is especially troubling given the drastic defense cuts sought by President Obama, which include reductions in funding for antisubmarine defense systems.”

The story has received relatively little attention since appearing in the conservative media outlet The Washington Free Beacon. According to the original report by longtime military correspondent Bill Gertz:

A Russian nuclear-powered attack submarine armed with long-range cruise missiles operated undetected in the Gulf of Mexico for several weeks and its travel in strategic U.S. waters was only confirmed after it left the region, the Washington Free Beacon has learned.

A Russian nuclear-powered attack submarine armed with long-range cruise missiles operated undetected in the Gulf of Mexico for several weeks and its travel in strategic U.S. waters was only confirmed after it left the region, the Washington Free Beacon has learned.

It is only the second time since 2009 that a Russian attack submarine has patrolled so close to U.S. shores.

The stealth underwater incursion in the Gulf took place at the same time Russian strategic bombers made incursions into restricted U.S. airspace near Alaska and California in June and July, and highlights a growing military assertiveness by Moscow.

Cornyn, a San Antonio Republican who sits on the Senate Armed Services Committee, says the report is “especially troubling given the drastic defense cuts sought by President Obama, which include reductions in funding for antisubmarine defense systems.”

A Pentagon spokesman, Navy Lieutenant Commander John Fage, dismissed Gertz’s report.

“We are aware of the reporting but we see nothing to indicate that it is true,” Fage told the Houston Chronicle.

Here’s the complete text of Sen. Cornyn’s letter:

Dear Admiral Greenert:... REST OF IT