Is insuring the uninsured a moral imperative?

Charles Krauthammer explains why the Senate and House health care reform bills should be “killed” and why Congress should opt instead for “targeted measures that attack the inefficiencies of the current system one by one — tort reform, interstate purchasing and taxing employee benefits.”
Krauthammer’s analysis is fully persuasive. However, near the end of his column he states that “insuring the uninsured is a moral imperative.”
This may be one of those issues best left for high school debate rounds or all-night college BS sessions. But for what it’s worth, my view is that “insuring the uninsured” does not rise to the level of a moral imperative.
It would, I think, be highly desirable if every American had health insurance. But I’m hard-pressed to understand why it’s morally imperative that some Americans pay for the health insurance of other Americans who can afford (even if not comfortably) to pay it themselves. This is tantamount to attaching a moral imperative to the transfer of income from the well-off to those who are less well-off but not poor.
Krauthammer may not be asserting such a moral imperative. He may instead have in mind a regime that requires those who can afford health insurance to purchase it and that assists them by lowering the cost through such measures as interstate purchasing.
It seems to me that reasonable people can disagree on the merits of requiring everyone to purchase health insurance. One argument against this requirement is that healthy, young Americans should not be forced to make what they reasonably consider to be a bad economic decision. To the extent that plausible arguments exist on both sides of this question, I can’t find a moral imperative in favor of either.
Finally, if Krauthammer is right that insuring the uninsured is morally imperative, one can argue that he is wrong to reject legislation that would largely accomplish this right away, in favor of targeted measures that, at best, will only move us gradually towards meeting our moral imperative.
As I see it, there are only a very small number of moral imperatives, and those few things that rise to that level must, by definition, be satisfied immediately, to the extent possible.
JOHN adds: I also find it odd that Krauthammer, a conservative, appears to think that there is a moral imperative for the government to supply everyone with health insurance. In general, moral imperatives apply to people, not governments. An individual might well conclude that he is under a moral imperative to help other people get vitally needed medical care (as opposed to, say, cosmetic surgery or Viagra prescriptions). In fact, a great many Americans do feel such a moral imperative, which is why they donate to countless charitable organizations that provide or finance health care. What governments should do is not respond to bogus “moral imperatives,” which generally involve transferring money from one citizen to another, but rather pursue sound public policy. Krauthammer demonstrates that the Democrats’ proposals represent awful public policy. He should leave it at that.