Vermont 's constitution states explicitly that "the people have a right to bear arms for the defense of themselves and the State" and those persons who are "conscientiously scrupulous of bearing arms" shall be required to "pay such equivalent."
Nanzi Pelosi is making her justification out of whole cloth.
But State constitutions cannot run afoul of the US Constitution.
It would make for an interesting case.
That being said, there are two arguments on which to base this:
1. The Vermont constitution requires those choosing not to bear arms to pay an equivalent; and
2. The benefits of gun ownership include a 'halo' effect - that is, non-gun-owners benefit materially through reduced crime, etc. and should pay some cost for the benefit.