Trump National Security Advisor Mike Waltz Departs for UN Ambassador Job Amid Maritime Policy Momentum

White House National Security Adviser Mike Waltz is set to leave the administration following controversy over sharing sensitive military information, departing amid significant developments in U.S. maritime policy which he helped shape.

President Trump confirmed his departure in social media post, saying he will nominate Waltz to be the next U.S. ambassador to the United Nations. Secretary of State Marco Rubio will serve as National Security Advisor in the interim, Trump said.

Waltz, a former Green Beret and Florida congressman, faced criticism in March for adding journalist to a private Signal chat used for planning a March 15 military operation against the Houthis in Yemen.

His exit coincides with major developments in maritime policy, notably President Trump’s April 9 executive order “Restoring America’s Maritime Dominance,” which established a comprehensive Maritime Action Plan (MAP) to bolster U.S. maritime industries. This executive order builds upon Waltz’s year-long push for maritime reform, which began with a bipartisan letter to President Biden in January 2024 calling for prioritization of U.S. maritime defense.

“President Trump is restoring America’s Maritime Dominance by signing an executive order to resurrect the U.S. Maritime Industry and increase our competitiveness with China!,” Waltz wrote on X earlier Thursday.

Prior to serving as National Security Advisor, Waltz had been deeply involved in maritime policy reform. In May 2024, he co-authored the “Congressional Guidance for a National Maritime Strategy” report with Senators Kelly and Rubio, and Representative Garamendi. He followed this with a Wall Street Journal op-ed urging maritime industry revitalization, and participated in policy discussions including an appearance on the ‘War on the Rocks’ podcast in August 2024 to discuss maritime strategy.

These efforts culminated in the SHIPS for America Act, which Waltz helped announce during a Center for Strategic and International Studies (CSIS) discussion in October 2024. The bill was reintroduced yesterday by a bipartisan group of lawmakers, including Senators Mark Kelly (D-AZ) and Todd Young (R-IN), along with Representatives John Garamendi (D-CA-8) and Trent Kelly (R-MS-1). The legislation aims to close the maritime capability gap between the United States and China—currently, China operates 5,500 ships in international commerce while the U.S. maintains only 80 flagged vessels.

Just today, Waltz described the bill as “game changer to restore America’s dominance.”

Throughout his career, Waltz has established himself as a prominent Iran hawk, consistently advocating for a hardline approach. As National Security Adviser, he maintained that “all options are on the table” regarding Iran—including military action—particularly concerning Iran’s support of Yemen’s Houthi rebels and its nuclear program.

Since resuming military strikes against the Houthis on March 15, the Trump Administration’s “Operation Rough Rider” has targeted over 800 Houthi sites in Yemen, resulting in the destruction of command-and-control facilities, air defense systems, and weapons storage locations.

“President Trump is taking decisive action against the Houthis to protect American personnel & assets, restore freedom of navigation, and deter our enemies,” Waltz wrote on X in March. “Biden’s feckless leadership emboldened the Houthis. Not anymore.”

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