Which multi-lateral attempts to curb the DPRK's nuclear program were taken?
1985: North Korea becomes a party to the NPT
1994: US-DPRK Agreed Framework, agreement to help North Korea with nuclear energy/food aid if it gives up nuclear weapons (US, South Korea, Japan).
Since 2006, 9 resolutions passed by the UN Security Council in favor of sanctions. Recent US Sanctions: 2008, 2010, 2013, 2015, 2016, 2017, 2022 covers arms and economic activities.
2017: Travel to and from DPRK from US suspended