Comment I'll give you six amendments: (Score 5, Insightful) 1633
Here are six amendments (not in any form of airtight legalese) that would be useful:
1: Campaign donations are forbidden. Each candidate for an elected office will get an equivalent place to state their platform. Advertising anything election related on a commercial (paid) basis will be a crime.
2: Similar to Article 9 of the Mexican Constitution: Only US citizens can influence the politics of the nation.
3: A "no confidence" vote can be done on Congress, forcing a complete re-election with no incumbents allowed in for the next term (but can run after that.)
4: Same as Article 23 of the Mexican Constitution. No double jeopardy, and after three trials, the defendant is now absolved of charges.
5: Same as Article 10 of the German Constitution, guaranteeing privacy.
6: The right to a firearm is guaranteed. However, part of school education is firearms training, from elementary school to high school. The purpose of this is to "un-Hollywoodize" firearms, and make them perceived as a tool (similar to a chainsaw or weed whacker), and no more. If packing becomes pedestrian or gauche, the gun control problem will go away by itself.
These are not perfect, but they will go a ways to address critical issues.