Show me where in the Constitution it says the government — created by the people in order to serve the people — is empowered to mandate that those selfsame people buy health insurance as a condition of living and breathing in the United States.

That was the pointed demand put to Democrats during the Obamacare debate. You remember those months: threats and bribes for every wavering moderate on their side of the aisle, while Republican opposition was steamrolled with accounting voodoo and parliamentary tricks that would have made Saul Alinksy blush. And what was their answer on the Constitution? Why, it was right there in the preamble, they told us. It expressly says, in black and white, that it is government’s job to “promote the general Welfare.”

This was absurd, of course. The preamble? Never had it been understood to have the meaning ascribed by Obamacare proponents, nor to have such potent force. Preambles are just hortatory and self-justifying, right? It is the subsequent articles, terms, and conditions that have the force of law. Oh no, countered Democrats: The preamble is basic, foundational to our understanding of everything that follows — and “promote the general Welfare” couldn’t be clearer. It was the license, we were to believe, for Leviathan to take over one-sixth of the private economy.

So, now comes the ludicrous strategic arms–reduction treaty (“New START”) with Russia that President Obama is curiously desperate to ratify before more Republican senators arrive on the scene next month. What does the president say about the treaty language that clearly straitjackets U.S. missile defense, holding our security in an ever more threatening world hostage to Soviet — er, sorry, I mean Russian — offensive capabilities?

He tells you, Don’t worry about it: That’s just the preamble. Doesn’t mean anything.

With his own credibility in tatters, the president has taken to channeling Ronald Reagan as he campaigns for New START. In that spirit, we should note that there are countless good reasons, substantive national-security reasons, for the senate to Just Say No. But how about we go with just two basic points, neither of which requires you to be an expert in telemetry or to know your ICBMs from your AMRAAMs? Let’s just focus on credibility and competence.

On New START, as on many other matters, the Obama administration has demonstrated that it is not to be trusted. That’s bad — no matter who the president is, we want to be able to credit him on vital issues of national defense. Nevertheless, when we hear these incessant Democratic invocations of the Gipper’s bon mot, “Trust but verify,” we ought to be thinking Barack Obama, not Vladimir Putin.

Trusting the Russian strongman is out of the question — wasn’t it only about ten minutes ago that President Bush was wiping egg off his face as the “strategic partner” whose soul he thought he had peered into rolled Red Army tanks into the heart of Georgia? But if we are going to trust Obama, we have to verify. The president notoriously says whatever he thinks he needs to say to achieve his objectives, and, with START in particular, the administration’s behavior has been abominable.

There is, as noted, the topsy-turvy matter of preambles. As National Review’s editors have pointed out, the New START preamble plainly touts “the interrelationship between strategic offensive arms and strategic defensive arms.” It further purports to cement for all time the current posture of this purported interrelationship, asserting that “current strategic defensive arms do not undermine” stability, and that the “interrelationship” between missile offense and missile defense “will become more important as strategic nuclear arms are reduced.” That is, the more we shrink our inventory of strategic nukes — the point of New START — the less latitude we will have to beef up our defense against missile attacks.