What is one responsibility that is only for us citizens?

One responsibility that is generally only for citizens is serving on a jury. While some countries may allow permanent residents to serve, most jurisdictions require citizenship to be eligible for jury duty. This is because jury service is considered a fundamental aspect of civic participation and the administration of justice within a democratic system, directly impacting the sovereign power of the state. Non-citizens may not have the same level of understanding of the legal system or the same vested interest in its fair application.