Was The Louisiana Purchase Unconstitutional? I

I have heard for years that Thomas Jefferson (and others at the time) believed that the Louisiana Purchase was unconstitutional, or at least that he had serious doubts about its constitutionality. I've never understood the issues. What were the objections? Were they well founded? Let take a look.

To begin with. let's try to understand the objections. Here is an excerpt from a letter that Jefferson wrote to Senator John Breckinridge (who should not be confused with this John Breckinridge) on August 3, 1803:

This treaty must of course be laid before both Houses, because both have important functions to exercise respecting it. They, I presume, will see their duty to their country in ratifying & paying for it, so as to secure a good which would otherwise probably be never again in their power. But I suppose they must then appeal to the nation for an additional article to the Constitution, approving & confirming an act which the nation had not previously authorized. The constitution has made no provision for our holding foreign territory, still less for incorporating foreign nations into our Union.

I don't know about you, but Jefferson's objection seems totally opaque to me. Was the United States going to be "holding foreign territory"? I didn't think so. The territory, once purchased, would belong to the United States. Would the US be "incorporating foreign nations into our Union"? Well, only in the sense that the U.S. was acquiring by treaty territory previously claimed by another country. But so what? Did Jefferson view these as different objections? Or were they two ways of phrasing the same thing? I'll explore these and other mysteries in future posts.