One month into Russia's invasion of Ukraine, senior Pentagon officials are brimming with newfound confidence in American power, spurred by the surprising effectiveness of U.S.-backed Ukrainian forces, Russia's heavy battlefield losses and the cautionary lessons they believe China is taking from the war.
A senior Pentagon official said the past few weeks have shown that the United States can marshal its "primacy in the global financial system" and its network of allies "in ways that can absolutely pummel aggressors."
The Ukrainian military's will to fight and ability to inflict heavy losses on larger and more technologically advanced Russian forces has taken many at the Pentagon by surprise.
"I think Ukraine has been able to tie the Russians in knots in large part because of what we've been able to do to help them since 2014," said the senior defense official, speaking on condition of anonymity. The official added that the failures of Afghan forces "might" have caused U.S. officials to underestimate Ukrainian troops.
Critics note that the Russian invasion is only 1 month old and that the Russians already are using their overwhelming firepower advantage to level Ukrainian cities in an attempt to secure a victory.
The United States also has relied heavily on European allies, who have often taken the lead in leveling crippling sanctions on the Russian economy at considerable costs to themselves.
"We need to demonstrate our [collective] power every day, and we can only demonstrate it if we keep everybody together," said Ivo Daalder, president of the Chicago Council on Global Affairs and a former U.S. ambassador to NATO. "This is not something the U.S. has traditionally done well."
Some Republicans have charged that Russian President Vladimir Putin's perception of the United States and its allies as militarily weak or unwilling to fight gave him the confidence to invade Ukraine. Rep. Michael McCaul of Texas, the top Republican on the House Foreign Affairs Committee, this month compared Biden to Neville Chamberlain, the former British prime minister who sought to appease Hitler before World War II.
"Weakness invites aggression. It's a historic axiom. And it's true," McCaul said.
Pentagon officials contend that there was little they could do to deter Putin, who expected a quick and easy victory in Ukraine, and argue that their broader strategy of "integrated deterrence" -- which leverages economic, diplomatic and military power to dissuade potential aggressors -- has so far worked to stop Putin from expanding the war into NATO territory. The Biden administration has made integrated deterrence the cornerstone of its soon-to-be released National Defense Strategy, which was delayed as the threat of an invasion grew.
"I don't think there's any doubt that the model of integrated deterrence comes out smelling pretty good from this," the senior defense official said.
Others pointed to Putin's Ukraine invasion as proof of the concept's failure. Rep. Mike Gallagher, R-Wis., said that he "completely and strongly" disagrees with anyone who cites Ukraine as an example of the success of integrated deterrence. "I cannot fathom how they can make that argument with a straight face," he said. "Their whole deterrence strategy rested on the idea that the threat of limited sanctions could deter Putin."
Gallagher added that the Ukraine conflict "could still escalate in ways that we don't foresee right now."
The biggest critique from Republicans has been that President Joe Biden and the Pentagon have been too quick to foreclose military options and too worried that aggressive U.S. efforts to arm the Ukrainians might spur Putin to widen the war.
More robust U.S. involvement "would be an assurance that Russia would lose the war," said Kori Schake, the director of foreign and defense policy at the conservative American Enterprise Institute. "If the Ukrainian military can fight the Russian military to a standstill, imagine what it would look like if the United States and its allies joined?"
The Biden administration's worries about triggering a wider war against a nuclear power, however, haven't constrained U.S. ambitions regarding Ukraine. A few weeks ago there was doubt among senior U.S. military officials about whether the Ukrainians could hold onto their country if Putin was determined to launch an all-out invasion. Now Pentagon officials talk of the need to make certain Putin suffers a "strategic failure."
Such an outcome, these officials said, would have far reaching consequences in Moscow but also in Beijing, where China's Xi Jinping is almost certainly drawing lessons from Putin's struggles.
"Amphibious landings are the single hardest large-scale military operations that there is," the senior Pentagon official said. Since the start of the Ukraine invasion, Russia has kept its amphibious ships parked off the coast of Ukrainian cities. At least one of those ships, thought to be carrying armored personnel carriers and tanks, was struck by Ukrainian forces Thursday in the Black Sea port of Berdyansk, resulting in a huge fireball.
Compared with Ukraine, Taiwan is a "hellscape" for an invading force that combines open beaches, mountainous terrain and dense cities, the senior defense official said.
Former Defense Secretary Robert Gates offered a similar assessment Wednesday in an online conversation with Michael Vickers, his former undersecretary of defense for intelligence. Xi and Putin have both described the United States as "in decline," politically paralyzed and eager to pull back from the rest of the world.
"Xi's got to wonder about his own army at this point," Gates said. "The resistance of the Ukrainians has got to make him wonder, 'Maybe I've underestimated the consequences of a military attack on Taiwan?'"
Gallagher took the opposite lesson, arguing that even though China recognizes Russia's struggles, Putin's gamble should spur a greater sense of urgency regarding Taiwan. "All of the evidence suggests that we are already in the window of maximum danger," he said.