Senate Republican Leader Mitch McConnell (Ky.) on Tuesday said the months-long delay in sending military aid to Ukraine has undermined its chances of defeating Russia on the battlefield and was premised on what he called the “sheer fiction” perpetuated by some colleagues that supporting Ukraine is not a vital national security interest.

“So much of the hesitation and shortsightedness that has delayed this moment is premised on sheer fiction. And I take no pleasure in rebutting misguided fantasies,” McConnell said in a floor speech responding to colleagues in both chambers who have dragged out consideration of military aid for Ukraine since President Biden requested it in October.

“Make no mistake: Delay in providing Ukraine the weapons to defend itself has strained the prospects of defeating Russian aggression. Dithering and hesitation have compounded the challenges we face,” he declared.

McConnell aimed his pointed remarks at critics within his party — including Sen. JD Vance (R-Ohio) — who have argued the Ukraine aid package won’t turn the tide of the war and have questioned whether the United States even has the industrial capacity to enable Ukraine to match Russia’s arsenal of drones, missiles and 155 mm artillery shells.

Vance wrote in a New York Times op-ed last month “the math on Ukraine doesn’t add up.”

“Fundamentally, we lack the capacity to manufacture the amount of weapons Ukraine needs to supply to win the war,” he wrote.

But McConnell on Tuesday reiterated his argument that the $95 billion foreign aid package will bolster U.S. arms production as well as the domestic economy.

“Across Europe, the acceleration of defense spending is outpacing our own. And right now, allies and partners from Europe to the Indo-Pacific have contracted more than $100 billion dollars worth of cutting-edge American weapons and capabilities,” he noted.

“Our allies across the world are buying expensive, sophisticated American weapons, produced in American factories by American workers. Do my colleagues really think that will continue if America decides that global leadership is too heavy a burden?” he asked.

McConnell also warned colleagues about the stakes for U.S. national security, warning that abandoning the war in Ukraine would only embolden the nation’s adversaries, including Iran and China.

“Failure to reestablish deterrence against Iran means encouraging unchecked terrorist violence against American personnel, our ally Israel, and the international commerce that underpins our prosperity,” he said.

“And failure to match the pacing threat — the People’s Republic of China — means jeopardizing the entire system of alliances that preserve American interests and reinforce American leadership,” he added.

McConnell said fellow senators who dismiss the value of U.S. alliances “ignore what history teaches about times when we lacked such friendships.”

And he noted that U.S. allies such as Japan fully understand the potential reverberations of Russian victory in Ukraine and what it would likely mean for Chinese ambitions in the Far East.

Japanese Prime Minister Fumio Kishida urged lawmakers during an address to Congress earlier this month not to doubt what he called the United States’s “indispensable” role in world affairs.

McConnell echoed that view in his remarks Tuesday.

“American prosperity and security are the products of decades of American leadership,” he said.

And he argued “our global interests come with global responsibilities” and that “healthy alliances lighten the burden of these responsibilities.”

“And at the end of the day, the primary language of strategic competition is strength,” he said.