For the past decade, left-wing Democrats have calibrated their actions by assessing whatever Donald Trump wants, and doing the opposite. This tactic is evident everywhere, but far fewer people understand how close this pattern comes to triggering a constitutional crisis.

One recent example came after the Trump administration officially withdrew the United States from the World Health Organization (WHO) on January 22. “Like many international organizations, the WHO abandoned its core mission and acted repeatedly against the interests of the United States,” announced Secretary of State Marco Rubio and Health and Human Services Secretary Robert Kennedy. “Although the United States was a founding member and the WHO’s largest financial contributor, the organization pursued a politicized, bureaucratic agenda driven by nations hostile to American interests.”

The U.S. Congress reserved the right to withdraw from the WHO when it joined the U.N. organization in 1948. President Trump initiated the process in the waning months of his first administration in response to its mismanagement of the COVID-19 pandemic. President Joe Biden suspended this withdrawal in 2021, but President Trump reinitiated it in 2025. Each of these policy reversals came as American voters decided to exchange one party for the other.

Now, some of Biden’s fellow Democrats have decided that they will simply refuse to follow the Trump administration’s foreign policy lead and engage with the WHO on their own.

On January 23, California Governor Gavin Newsom (D) announced that his state was “becoming the first, and currently the only, state to join WHO’s Global Outbreak Alert & Response Network (GOARN).” Newsom met with WHO Director-General Dr. Tedros Ghebreyesus during the World Economic Forum “to detect and respond to emerging public health threats.”

In Newsom’s announcement, foreign policy disagreement with the Trump administration features prominently. “The Trump administration’s withdrawal from WHO is a reckless decision that will hurt all Californians and Americans,” Newsom declared. “California will not bear witness to the chaos this decision will bring. We will continue to foster partnerships across the globe.”

On February 3, Illinois Governor J.B. Pritzker (D) made a similar announcement for similar reasons. “By withdrawing from the World Health Organization, Donald Trump has undermined science and weakened our nation’s ability to detect and respond to global health threats. I refuse to sit idly by and let that happen,” Pritzker protested. “By joining the World Health Organization’s coordinated network, GOARN, we are ensuring that our public health leaders — and the public — have the information, expertise, and partnerships they need to protect the people of our state. Across our state and alongside valued partners around the world, Illinois will continue to put science, preparedness, and people first.”

The Illinois Department of Public Health outlined the benefit from WHO membership resources, such as “Direct access to global early-warning alerts and outbreak intelligence,” “Opportunities for technical collaboration and surge support during major public health events,” “Participation in international training, exercises, and best-practice exchanges,” and “Stronger coordination between state-level public health systems and global response efforts.”

Never one to miss a bandwagon hurtling to the left, the New York City government under Mayor Zohran Mamdani (D) also jumped on board the trend on February 5. “New York City is a global city with 8.5 million residents and more than 12 million international visitors every year,” explained New York City Acting Health Commissioner and Chief Medical Officer Michelle Morse. “To best prevent disease outbreaks and public health emergencies and to protect New Yorkers and visitors from them, the NYC Health Department is joining hundreds of public health institutions worldwide that share critical public health information to support life-saving prevention and response efforts. Infectious diseases know no boundaries, and nor should the information and resources that help us protect New Yorkers.”

The problem with all of this talk of international cooperation and its benefits is that American states and cities are not allowed to have their own foreign policy. Article I, Section 10 of the Constitution stipulates that “No State shall enter into any Treaty, Alliance, or Confederation.” In fact, “No State shall, without the Consent of Congress … enter into any Agreement or Compact with another State, or with a foreign Power.”

The original reason for the 13 “States of America” to become “United” was to present a unified front on matters of foreign policy. State governments have sovereignty, but only over their domestic affairs. Once that principle is breached, once individual states begin forging independent side-partnerships with foreign governments, American unity would be fundamentally compromised, and American security with it.

Consider the implications of California universities collaborating with the Chinese Communist Party on defense research, or the Texas Military Department sharing intelligence with a foreign power, independent of the federal government.

What California, Illinois, and New York City are proposing is a uniquely unconstitutional manifestation of nullification, where states unilaterally declare federal law to be null and void in their territory.

The Constitution Center records at least “three prominent attempts by states at nullification in American history.” Kentucky tried to nullify the Alien and Sedition Acts in 1798. South Carolina tried to nullify federal tariffs in 1832 (with slavery providing an ugly backdrop). Arkansas tried to nullify Brown v. Board of Education in 1957.

For decades, progressives have derided southern states for their past nullification attempts. Now, it appears that such derision was based on the unfounded belief that progressive values would always (or eventually) prevail in the U.S. federal government. However, progressives have grown increasingly alarmed with their lack of power over federal policy, to the point that they have begun embracing their own versions of nullification.

For instance, Pritzker recently opined, “We need ICE out of our cities and, frankly, out of our state.” What is this but an attempt to dictate where federal officers can enforce federal law? Any expression of “ICE Out” is really an endorsement of the constitutionally illegitimate principle of nullification. (In contrast, a declaration that state or local law enforcement “does not enforce federal immigration law” is simply a recognition of the fact that states enforce state laws, and the federal government enforces federal laws.)

On December 10, 1832, President Andrew Jackson described nullification as “the strange position that any one State may not only declare an act of Congress void, but prohibit its execution,” and that “the true construction” of the Constitution “permits a State to retain its place in the Union and yet be bound by no other of its laws than those it may choose to consider as constitutional.” Such a position, Jackson argued, was absurd, “having for its object the destruction of the Union.”

Only one element of uncertainty may save the decision by progressive jurisdictions to join the GOARN network from being an indefensible violation of the Constitution. One could make a case that GOARN’s cooperation is not so much with a foreign government or international organization as with a global network of research institutes. GOARN has at least 365 partner institutions, of which 36 are in the United States.

Under this theory, these three progressive governments are not directly rejecting the Trump administration’s decision to withdraw from the WHO; that point might save them constitutionally, but it defeats the whole point of their choosing to join GOARN as a way to stick a finger in Trump’s eye.