Senate Minority Leader Mitch McConnell (R-Ky.) is generally pretty cautious with his choice of words, so it’s probably not an overreaction to take note of subtle shifts in rhetoric.

One word can say a lot, as Senate Republican leader Mitch McConnell showed Sunday.

In an interview on “Fox News Sunday,” McConnell reiterated previous Republican opposition to higher taxes but changed one word by specifying that he and the GOP are against higher tax “rates.”

“You cannot get anywhere if you start raising tax rates,” the Kentucky senator said in discussing negotiations with President Barack Obama and Democrats on a deficit reduction plan.

Previously, McConnell and other conservative Republicans have railed against higher taxes in any form, and McConnell’s use of the term “tax rates” indicated a shift in the mainstream GOP position.

Host Chris Wallace, to his credit, picked up on this, but McConnell brushed off follow-up questions.

At a certain level, I can appreciate why all of this seems a little silly. An increase in taxes vs. an increase in tax rates probably looks like a hair-splitting exercise to most folks.

But McConnell’s subtle shift, if deliberate and sincere, may point in an encouraging direction. He’s still not willing to return to Clinton-era tax rates for anyone, but as of yesterday, he’s apparently willing to consider increased revenue.

What’s the difference? Some in the GOP, including Gang of Six participants, believe they can get additional revenue to help shrink the deficit by closing tax loopholes and changing deductions for individuals and/or corporations. Tax rates would stay the same, but tax revenue would go up.

Obviously, the devil would be in the details, and “tax loopholes” is quickly becoming the new “waste, fraud, and abuse” in the category of hollow policy ideas. Some of the same Republicans eager to close the loopholes and bring in additional funds struggle to identify exactly what loopholes they’re willing to close.

But in the abstract, this could be a big step. Many on the right (see Norquist, Grover) count closing loopholes as tax increases, and such a move is therefore considered an ungodly abuse on all that is good and holy. If McConnell is now open to doing it anyway, it’s encouraging.

Perhaps more importantly, the standard GOP line is that the government shouldn’t bring in another penny in revenue from anyone at any time. If McConnell is prepared to move away from this nonsense, it makes the prospect of a compromise at least marginally better.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.