Secretary of State John Kerry signed an international treaty on arms regulation Wednesday, angering conservative lawmakers and rattling the National Rifle Association despite claims that the treaty won’t infringe on gun rights.

So what’s all the fuss about?

The treaty, which took seven years to negotiate, would regulate the $70 billion global trade in conventional arms. The U.S. is the largest arms exporter in the world, and Kerry’s signature was seen as a significant step in pushing it forward.

Supporters say the treaty sends a bold global message advocating the first-ever moral standards on the cross-border trade linked to human rights violations around the world. But to some on U.S. soil, the treaty treads into dangerous territory and could step on the constitutional rights of Americans.

They point in part to language, at the very beginning of the document, that includes “small arms and light weapons” and worry this could cover firearms owned by Americans.