The worst feature of arguments over the use of government power to enforce particular moral outcomes is the tendency of the winners to sweep away all objections by means of their claim to righteousness. Thus with some of Paul's critics: Don't give us that stuff about what the Constitution allows or what the prescribed powers of government should be! Give us the results that Humanity demands!
A kind of ends-justifies-the-means framework encases this grand assumption. If we're right, we're right, and that's all anybody needs to know. Paul proves himself less the politician -- quick to duck complexity -- than the amateur who just says what he thinks; a dangerous habit that, in an anti-establishment year, could boost his standing materially, to the dismay of the moral police.
We'll see. Meantime, inadvertently, the Libertarian Republican from Kentucky reminds us why the power of government remains a less certain instrument for effectuating moral change than does a general change in moral opinion. Pretty much the same thing Barry Goldwater said!
Government is all about the deployment of power, often as a means of appeasing resentments. That very exercise of power can provoke countervailing resentments, as in, how dare they tell me I can't ... !? Recall, for instance, how the federal judiciary's insistence on racial balance busing as a cure for racial isolation helped deplete the public schools of white students.
In reform movements, you want to keep the government out for as long as possible. Alas, in reform movements, the political tendency is to jump in with all four feet. I do believe that's where we came in.