U.S. Arms Sent to Ukraine Would Blunt but Not Stop a Russian Invasion

WASHINGTON — President Biden has ruled out sending U.S. troops to fight in Ukraine, but American-made weapons are already there in force and more could be on the way. How effective they would be in turning back a Russian invasion is another question.

Since 2014, the United States has committed more than $2.7 billion in security assistance to Ukraine, according to the Pentagon, including a $200 million package in December comprising equipment like Javelin and other anti-armor systems, grenade launchers, large quantities of artillery, mortars and small-arms ammunition.

But military experts say that with 130,000 troops on three sides of Ukraine, the Russian Army could quickly overwhelm the Ukrainian military, even one that is backed by the United States and its European allies. Ukrainian forces stretched thin by defending multiple borders would have to prioritize which units received advanced weaponry and extra ammunition.

Ukrainian troops — trained in recent years by U.S. Army Green Berets and other NATO special forces, and better equipped than in Russia’s last invasion in 2014 — would likely bloody advancing Russian troops. But a long-term Ukrainian strategy, American officials said, would be to mount a guerrilla insurgency supported by the West that could bog down the Russian military for years.

“All of this equipment and training will help the Ukrainians resist in an insurgent form and conventionally,” said Evelyn Farkas, who served as deputy assistant secretary of defense for Russia, Ukraine and Eurasia in the Obama administration.

Sending weapons to Ukraine is important, said James G. Stavridis, a retired four-star Navy admiral who was the supreme allied commander at NATO, but even more pivotal may be less visible countermeasures: American intelligence to help pinpoint Russian forces and new tools to defend against crippling cyberassaults and to counterattack Russian military communications.

The effectiveness of the American military aid will largely hinge on what President Vladimir V. Putin of Russia orders his forces to do, military analysts said.

If Russia launches mostly air and missiles strikes, the equipment does not help that much, said Rob Lee, a former U.S. Marine officer and Russian military specialist at the Foreign Policy Research Institute in Philadelphia. Absent in the influx of American military aid are advanced air defenses, like Patriot antiaircraft missile systems.

If Russian forces invade but do not intend to occupy the country, the weaponry also might not be that significant, Mr. Lee said. But if Russian forces seek to occupy the country or go into major urban areas, the weapons — and any future supplies from the United States — could help sustain an insurgency.

To underscore the potential consequences for Russia, the chairman of the Joint Chiefs of Staff, Gen. Mark A. Milley, delivered a stark message to his Russian counterpart when they spoke in late December: Yes, General Milley said, the Ukrainian military stands little chance of repelling the larger, better armed Russian force.

But a swift victory would be followed, General Milley told Gen. Valery Gerasimov, by a bloody insurgency, similar to the one that led the Soviet Union to leave Afghanistan in 1989, according to officials familiar with the discussion.

General Milley did not detail to General Gerasimov the planning underway in Washington to support an insurgency, a so-called “porcupine strategy” to make invading Ukraine hard for the Russians to swallow. That includes the advance positioning of arms for Ukrainian insurgents, including Stinger antiaircraft missiles, that could be used against Russian forces.

The United States began using social media to highlight the transfers of weapons to the government in Kyiv shortly after it first became clear that Mr. Putin was amassing a potential invasion force along his country’s border with Ukraine. The messaging from the United States has not been subtle, with the government releasing photographs of planeloads of weapons and equipment.

Additional aid could be on the way. On Capitol Hill, senators in both parties have coalesced behind legislation that would authorize Mr. Biden to use the Lend-Lease Act of 1941, last used in World War II, to lend military equipment to Ukraine.

The bill, led by Senators John Cornyn, Republican of Texas, and Jeanne Shaheen, Democrat of New Hampshire, is part of a package of bipartisan sanctions targeting Moscow that lawmakers are negotiating, though a spokesman for Mr. Cornyn said that senators were also exploring other avenues for passing the bill given its broad support in the Senate.

“The circumstances today are not those of March 1941,” Mr. Cornyn said. “There is no mistake about that.” But he added that the historical parallels were “chilling” and that “the lessons of the past must inform the present.”

Since becoming an independent nation, Ukraine has largely stuck with the family of weapons designed by the Soviet Union. That can be seen in the Ukrainian Army’s use of Kalashnikov-type assault rifles instead of the M16s and M4 carbines used by the United States and many other Western militaries.

That began to change after Russia’s annexation of Crimea in 2014, with the United States providing hundreds of antitank missiles and other weapons to Ukraine. “The number of Javelins given to Ukraine numbered in the many hundred before these recent shipments were made,” said Alexander Vindman, a retired Army lieutenant colonel who oversaw European affairs on the National Security Council from 2018 to 2020. “And now that number has increased by hundreds and up to several thousand when including advanced anti-armor capability provided by NATO allies,” he added.

“Alone, they won’t drive Russia’s decisions for military offensive, but will affect the calculus around the costs and benefits of military action,” Colonel Vindman said. “Javelins would be highly effective in ambushes and Russia would have to account for them in certain ways, including forcing Russia to employ air power against soldiers using them.”

Although the Pentagon has not specifically said it was sending NATO-standard firearms like machine guns to Ukraine, it has shared photos of ammunition it has shipped to Kyiv. On Feb. 3, the Pentagon tweeted photos of an arms shipment to Ukraine that included dozens of crates, each containing 800 rounds of belted 7.62-mm ammunition chambered for NATO machine guns like the Belgian-designed M240 commonly carried by Western infantry troops and mounted in vehicle turrets.

Another important weapon is the Javelin, a relatively lightweight guided missile developed specifically to destroy Soviet armored personnel carriers and tanks. But unlike previous generations of American portable antitank weapons like the TOW missiles supplied to Syrian rebels, which require the operator to stay in place after firing and optically guide the missile to its target, the Javelin locks onto its targets so that soldiers using it can move as soon as the missile is fired — limiting their exposure to any return fire.

The Javelin has two other features that make it attractive to militaries: a single missile contains two explosive warheads — one behind the other — that can defeat modern types of advanced armor typically found on the front and sides of Russian tanks. It can also be set to fly upward and then descend nearly straight down on the top of a vehicle, where its armor is thinnest. Soldiers require little formal training to use the Javelin launcher effectively.

Other American-made weapons are flowing in from NATO allies. In a series of Twitter messages last weekend, the State Department posted photos of American-made Stinger antiaircraft missiles coming from Lithuania to Kyiv. In the 1980s, the C.I.A. covertly supplied less-advanced versions of these Stingers to mujahedeen fighters in Afghanistan that were used to shoot down low-flying Russian helicopters and airplanes.

To be sure the message was not lost on its intended audience, the State Department tweeted the Stinger photos with accompanying messages in Russian as well as in Ukrainian and English.

Ukraine is tapping other sources for advanced weaponry. President Recep Tayyip Erdogan of Turkey agreed earlier this month to supply one of the Ukrainian Army’s most sophisticated weapons — a long-range, Turkish-made armed drone whose use in combat for the first time in Ukraine last fall infuriated Russian officials.

When governments covertly supply arms to another country or to a fighting group, they may grind serial numbers off firearms or paint over the markings on munitions crates that identify the weapons and their country of origin.

That, however, has not been the Defense Department’s recent approach to Ukraine.

In many of the military’s tweets, the accompanying photos showed coded markings painted on crates or shipping tubes that were clear enough to discern not only their contents but even the month and year they were made and the factory they came from, such as one showing a stack of Javelin missile tubes made in October 2003 at Lockheed Martin’s nearly 4,000-acre manufacturing facility in Troy, Ala.

Catie Edmondson contributed reporting.