The Declaration does have one legal effect - it sets the legal date of American independence, to the extent that may become an issue in an American court.
The issue had some significance immediately after the War, when it became a key point in deciding whether certain individuals remained British subjects or acquired U.S. citizenship. The American courts determined that if an American-born British subject left the U.S. within a reasonable time after the Declaration, they retained British nationality and did not acquire U.S. citizenship. If they stayed, then they lost their British status and became American citizens.
The British courts reached a similar conclusion, but used a different date: the Treaty of Paris of 1783. It was only at that time that the British government recognized U.S. independence, so that was the date the British courts used.
So the Declaration did have some legal effect, but only within the domestic American court system. It’s hard to imagine that having much day-to-day significance in the courts today, but you never know…
Lets note that this is so only from a legal standpoint and only because of our traditional political structure. Judges don’t control what the Constitution means in any absolute sense. If a judge rules that the Constitution means that the sky is green, to take a ridiculous example, of course the sky wouldn’t change color. On another level their pronouncements are not any more valid than anyone elses opinion, except in a court of law. That is: if Justice Scalia and I debate in a bar the meaning of a constitutional clause he isn’t somehow magically right just because of his position. I could very well have the better argument… in the bar. In court his opinion is authoratative, of course. But the courts’ opinion is controlling only because we allow it to be so. If the legislative and executive branches had rejected the notion of judicial review when it was promoted in Marbury v Madison and instead declared Congress as the arbiter of the meaning of the Constitution then their opinion would be controlling.
Can you cite this assertion? Main does list Jefferson with the “Antifederalists” but doesn’t give his reasons for doing so. I know that Jefferson criticized the federal convention both for it secrecy and for its lack of a bill of rights but am unaware that he went further.