“We are much better sustaining our effort now, seeing this to success, than having to pay a much higher price later when we have to deal with a world full of aggression,” he said.

Austin also argued that not sending aid to Ukraine increases the likelihood that American troops might one day face combat against Putin’s forces in defense of a NATO ally in Europe.

“If Putin is successful, he will not stop at Ukraine,” Austin said. “If you’re a Baltic state, you’re thinking you’re next, and there’s no question in my mind that sooner or later, he will challenge NATO and we’ll find ourselves in a shooting war.”

Blinken and Austin’s plea for lawmakers to keep Biden’s emergency aid package intact comes as the Senate and House are on a collision course over Ukraine aid.

New Speaker Mike Johnson plans to hold a vote on legislation that grants $14.3 billion in military funding for Israel, matching Biden’s request for that country but leaving out money for Ukraine. The Republican-led bill also offsets the new Israel aid with cuts to the Internal Revenue Service. The move is a non-starter in the Senate and likely means many House Democrats will oppose the bill this week.

In separating Israel aid, Johnson argued the fight against Hamas after this month’s brutal attacks is the most urgent need. But Senate leaders, including Majority Leader Chuck Schumer and Minority Leader Mitch McConnell, argue lawmakers should pass aid for both countries in the same package.

Biden’s proposal includes over $60 billion to continue to assist Ukraine. A previous $24 billion Ukraine request the White House submitted in August, meant to help Kyiv in the first quarter of the fiscal year, has languished on Capitol Hill.

Pressed on how long Ukraine can hold out if more funding isn’t approved, Austin said it’s a “guarantee” that Russia will prevail.

“It’s hard to put a timeline on exactly how long it would take, but I guarantee that without our support, Putin will be successful,” Austin said. “If we pull the rug out from under them now, Putin will only get stronger and he will be successful.”

Administration officials made the case that the Israeli and Ukrainian fights are linked because Tehran supplies drones and other weapons Russia’s military has used to attack Ukraine’s infrastructure. Russian technology, according to Blinken, is making Iran’s arsenal “more sophisticated.”

“That could be used against Israel or potentially against us, against our forces, against our personnel, either directly or via Iranian proxies,” Blinken said

“This two-way relationship is of increasing concern to us, and one we have to be acting against resolutely in both theaters, because they’re closely linked,” Blinken added.

Cutting off support for Ukraine would also embolden China, and weaken America’s standing as a reliable ally, Austin argued. The administration’s emergency proposal also includes money aimed at deterring China in the Pacific and implementing the trilateral AUKUS submarine pact with the U.K. and Australia.

Senators on both sides of the committee voiced support for linking the two conflicts, in contrast to the House’s Republican skeptics of further Ukraine funding.

“We must recognize that our national security interests are being aggressively challenged by all these authoritarian actors,” said Senate Appropriations ranking Republican Susan Collins of Maine.

“We need to support Israel, they’re fighting for their very existence. … I believe we also need to support Ukraine,” said Sen. John Hoeven (R-N.D.). “If you look at history, you understand that tyrants, like Putin, don’t stop. They have to be stopped.”

At the same time, Hoeven nodded to a path for an ultimate deal on aid — including border security — by expressing dissatisfaction with the administration’s approach to migrants at the southern border. Homeland Security Secretary Alejandro Mayorkas is expected to testify before the committee next week on the border security funding Biden also sought in the package.

Senate Appropriations Chair Patty Murray (D-Wash.) also noted that more Ukraine funding is backed by “huge supermajorities” in both chambers.

“So getting this funding across the finish line should not be controversial,” Murray said.