On Tuesday, the White House confirmed that it has halted critical weapons deliveries to Ukraine, even though Ukraine remains under relentless Russian attack. This will only embolden Russia to continue its war, and make a just peace less likely.

For months, President Trump has played a cynical game. In front of the press, he threatens to impose new sanctions on the Russian economy. In private, he never follows through. He publicly suggests he might increase support for Ukraine; in fact, only last week, Mr. Trump said he would “see if we can make” additional air defense missiles available for the Ukrainian military. But behind the scenes he is halting supplies that were already committed to Ukraine.

All of this suggests that Mr. Trump is not willing to pressure Russia to end this war. Instead, he is folding and abandoning Ukraine.

The United States provides Ukraine with military aid through two main sources. Presidential drawdown packages are taken from U.S. military stockpiles, which are replenished with newer kits, a process that ultimately helps modernize the military. And the Ukraine Security Assistance Initiative provides funds to procure materiel directly from U.S. defense manufacturers.

In his final months in office, President Joe Biden authorized an additional $1.25 billion drawdown package and instructed the Pentagon to place all remaining U.S.A.I. dollars on contract. He also imposed new sanctions on the Russian oil sector and worked with the Group of 7 to secure a loan of $50 billion for Ukraine from the proceeds of Russian sovereign assets.

This summer, the drawdown deliveries that Mr. Biden authorized will run out. Mr. Trump has not announced any additional support packages, and now the Trump administration has paused outstanding security assistance deliveries to Ukraine, which were slated to provide the Ukrainian military with air defense missiles, rockets, artillery and other vital support well into next year.