Leverage to Enhance Effective Diplomacy Act of 2017 or the LEED Act This bill directs the President to: (1) impose property-blocking sanctions against the North Korean government, business entities that trade with North Korea, including specified Chinese entities, and affiliated persons or entities; (2) prohibit the opening, and strictly control the maintaining in the United States, of correspondent or payable-through accounts by a foreign financial institution that assisted in the importation, sale, or transfer of North Korean goods or services; and (3) impose specified sanctions against a person that imports, purchases, or transfers goods or services from the North Korean government or from such entities or affiliates. The North Korean Human Rights Act of 2004 is amended to extend assistance for human rights and democracy programs. The bill prescribes reporting requirements with respect to North Korea's ballistic missile and missile fuel program. The Department of State shall: (1) brief Congress on the status of U.S. diplomatic engagement with North Korea and of detained U.S. citizens, and (2) develop a diplomatic strategy to end the transfer of rocket fuels and chemical precursors to North Korea. The State Department may reduce its diplomatic presence in, and terminate or reduce foreign assistance to, countries that are not cooperating with diplomatic and economic efforts to isolate North Korea.