Yes he did. Jefferson corresponded with Madison, who in turn offered many of his suggestions in the convention. Madison in turn kept Jefferson up to date on the happenings of the convention. His autobiography indicates that he knew extensively of the document's formation and theories during the ratification debate. The fact that he did not campaign in opposition to the document, though he, like Mason, desired a bill of rights, is largely credited in facilitating ratification in Virginia. Madison could not have overcome Mason and Patrick Henry in a ratification fight had Jefferson endorsed their position.
In Federalist No. 78 Hamilton also wrote, 'Nor does this conclusion by any means suppose a superiority of the judicial to the legislative power. It only supposes that the power of the people is superior to both.'
Or this from No. 49:
'As the people are the only legitimate fountain of power, and it is from them that the constitutional charter, under which the several branches of government hold their power, is derived, it seems strictly consonant to the republican theory, to recur to the same original authority, not only whenever it may be necessary to enlarge, diminish, or new-model the powers of the government, but also whenever any one of the departments may commit encroachments on the chartered authorities of the others. The several departments being perfectly co-ordinate by the terms of their common commission, none of them, it is evident, can pretend to an exclusive or superior right of settling the boundaries between their respective powers; and how are the encroachments of the stronger to be prevented, or the wrongs of the weaker to be redressed, without an appeal to the people themselves, who, as the grantors of the commissions, can alone declare its true meaning, and enforce its observance?'Last time I checked we still had a 10th Amendment.