South Dakota v. Dole held that things like the drinking age can only be tied to related items. Road maintenance in exchange for road rules passes muster, and interstate highways is about as "interstate commerce" as you can probably get.
I'm not prepared to consider the Tenth extinct just yet. That is, among other things, a "you nuke us we nuke you" scenario between the two parties. Things like drinking age work because the two parties largely agree on it.
South Dakota v. Dole held that things like the drinking age can only be tied to related items. Road maintenance in exchange for road rules passes muster, and interstate highways is about as "interstate commerce" as you can probably get.
I'm not prepared to consider the Tenth extinct just yet. That is, among other things, a "you nuke us we nuke you" scenario between the two parties. Things like drinking age work because the two parties largely agree on it.