Reader M.G. flagged a line Mitt Romney used during Monday night’s debate and asked whether the Republican frontrunner is telling the truth. Let’s take a look at the Romney quote:

“[T]he most extraordinary thing that’s happened with this military authorization is the president is planning on cutting $1 trillion out of military spending. Our Navy is smaller than it’s been since 1917…. We simply cannot continue to cut our Department of Defense budget if we are going to remain the hope of the Earth.”

Romney is actually tying a couple of lies together with this argument. For one thing, Obama isn’t planning to cut $1 trillion out of military spending; he intends to cut about $450 billion and those savings would be spread out over a full decade.

But what about the shrunken U.S. Navy? It turns out that’s a line Romney uses quite a bit on the stump, and like a little too much of the former governor’s rhetoric, it’s intended to deceive the public.

The Romney campaign says the Navy is the smallest it’s been in 95 years based on the number of ships in its fleet. But as Tim Murphy explained, this isn’t a credible metric.

[E]ven by that standard, Obama’s Navy has more ships than at any point in the last four years of the Bush administration. The Navy’s downsized fleet was a result of a decades-long reorganization rather than any Obama administration policy. More to the point, we’re getting a lot more bang for our buck — we’ve swapped dreadnoughts, monitors, and 50-gun frigates for air-craft carriers and nuclear submarines. Which would you want in a fight?

And this again leaves us with one of two options. Romney is either (1) deeply confused about military policy, and didn’t do his homework before popping off on a subject he doesn’t understand; or (2) lying, hoping to fool voters, and counting on the media not to call him on it.

It’s an either/or dynamic that comes up all the time with the Republican frontrunner.

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.