Via Politico we learn that Claire McCaskill seems to be feeling her oats when it comes to the threatened GOP government shutdown over their OCD efforts to defund the Affordable Care Act (ACA):

I don’t think in America we should throw tantrums when we lose elections and threaten to shut down the government and refuse to pay the bills,” the Missouri Democrat said on “Fox News Sunday.” “The American people had a choice last November. They had a choice between someone who said repeal Obamacare, and President Obama.”

[. . .]

“I cannot believe that they are gonna throw a tantrum and throw the American people and our economic recovery under the bus,” she said of Republicans. “It is really gonna hurt real people. And this is just political point-making.”

McCaskill was feeling so empowered that she characterized the GOP shutdown antics as “Akin-itis.” (Well … duh! Did anyone ever really think that Todd Akin was an isolated phenomenon in the party of Galloping Old Poops?)

McCaskill’s GOP opposite number, though, Senator Roy Blunt, has a different take as you might expet. Nevertheless, there are plenty of hints that he’s a bit squeamish when it comes to the floor-kicking, full-out tantrum that folks like Ted Cruz are promising:

Blunt has given no indication of siding with a determined element promising every rules trick to keep the anti-heath law offensive alive. Before that moment comes, all Republicans can weigh in heartily on the new law.

“I’m no supporter of the president’s health care plan. I believe it won’t work, there’s evidence every day of that, and I’ll vote to not move forward with it,” he said in a Friday interview.

He added: “I don’t know where we’ll be in the middle of the week.”

What could account for McCaskill’s political vim and vigor and Blunt’s cautious and worried tone? Could it be, as Robert Kuttner points out, that an unpopular shutdown is a dangerous ploy for vulnerable Republicans:

This very high-profile mess, just a year before next mid-term election, could upend assumptions about 2014. Democrats need to pick up just 17 seats to take back the House. Most analysts put the number of at-risk Republican seats at between 20 and 25, meaning that Democrats would need to run most of the table. But a deeper look suggests that more Republican seats could be vulnerable. In 2012, Republicans won 41 seats with 55 percent of the vote or less. If Democrats hold their own seats and win back even half of those, they take back the Majority.

Of course, for Blunt the issue probably also threatens to have even more tellling blowback: the people who employ him, his corporate cronies, are aghast at the reckless abandon of his more extreme Tea Party congressional colleagues. The U.S. Chamber of Commerce has urged the GOPers to act in a more fiscally responsible manner. Even Wall Street recognizes the foolishness for what it is. The big money folks will fund any kind of stupidity as long as it gets pols sympathetic to their money-making needs into power. Where they draw the line, though, is when the stupidity spills over into financial lunacy – a fact that is surely not lost on Blunt. After all, as Slate’s John Dickerson puts it:

House Republicans aren’t just courting disaster. They’re helping President Obama make the case that they were the problem all along.

No wonder McCaskill is energized and Blunt suitably subdued.