01/08/2012 12:29 pm ET Updated Mar 09, 2012

Marco Rubio A Shoo-in For VP? Not So Fast

With Mitt Romney virtually certain to win the Republican nomination, speculation is already turning to his choice of a running mate. Sen. Marco Rubio (R-FL) seems to be at or near the top of almost everybody's list.

But I would strongly caution Mr. Romney against picking the freshman senator who is not only quite young and inexperienced but also has a tendency to say things totally untethered from reality. And I don't only mean his oft-repeated lies about having been born "to Cuban-born parents who came to America following Fidel Castro's takeover" (this quote is from his since-amended official Senate biography). Friday morning, Sen. Rubio sent a letter to president Obama regarding a routine increase in the debt ceiling.

Some statements in the letter really catch the eye. For instance, Rubio asserts, "It's a tragic reality but, on your watch, more and more people have come to believe that America is becoming a deadbeat nation inevitably heading toward a European-style debt crisis." This statement may be technically true -- in a sense that in spite of all evidence to the contrary, more and more people in the Republican base believe apocalyptic propaganda of the Tea Party. And it is indeed a tragic reality. But why is it Obama's fault?! Virtually nobody outside the Tea Party seems to share this belief. The demand for U.S. debt is actually at record high levels. The interest on 30-year bonds keeps hovering around 3% mark, the interest on 10-year notes is about 2% and the interest on all shorter-term debt is under 1%. Such interest rates are certainly a hallmark of a deadbeat nation!

The "European-style" qualifier is a nice touch. It is at least debatable whether America is heading toward some sort of a debt crisis in the long run, but there can be no debate about any possibility of that crisis being "European-style," since there is absolutely no chance that in any foreseeable future we will abandon the dollar in favor of some other currency not controlled by the U.S. government. It is quite possible that Sen. Rubio has not yet taken time out of his busy schedule to familiarize himself with any details of the Euro crisis and is using the word "European" (considered a dirty word by many in the Tea Party) simply the way the Brits use the word "bloody."

There is also this interesting paragraph in the letter: "Instead of making debt ceiling increases a routine Washington exercise, we need to make it routine to actually spend no more than we take in. Until then, I will oppose your request to continue borrowing and spending recklessly."

The first sentence expresses the senator's well-known preference for balanced budgets. But he never bothers to give a good explanation for his balanced budget fetishism. Routine budget deficits can be fiscally responsible if they are limited to just a few percent of the GDP. If the national debt on average increases slower than the nominal GDP, the debt-to-GDP ratio will keep decreasing and for all practical purposes we will be paying down the debt. So don't need to eliminate the trillion dollar deficit -- just cut it to a more manageable half-a-trillion-dollar deficit.

The second sentence makes it clear that Sen. Rubio wants to balance the budget not in some unspecified future, but immediately. We are just starting to recover from the worst financial crisis in three quarters of a century, and the danger is not over yet -- millions of homeowners are still seriously underwater and the consumer demand is still weak, plus the Euro crisis may get much worse at any moment. Eliminating the deficit this year would require some combination of huge tax increases and drastic spending cuts, and any such combination would devastate the economy.

If Marco Rubio is a candidate for vice-president, Joe Biden will crush him in the VP debate (using the arguments similar to those I have just outlined) and make him look even less prepared than Sarah Palin.