Ukraine’s success ramps up Putin threat

The head of the U.S. intelligence community warned Tuesday there's no "viable" prospect for peace negotiations in Ukraine in the near term, predicting a protracted "war of attrition" that's likely to become "more unpredictable and escalatory."

Why it matters: The U.S. is doubling down on helping Ukraine defeat Russia on the battlefield but with little clarity about how the war ends. That means the mammoth $40 billion package of additional security and financial assistance set to pass the House on Tuesday night is unlikely to be the last.

The big picture: Out of nearly a dozen Republican and Democratic senators Axios spoke to Tuesday, not one said they believe the U.S. is in a "proxy war" with Russia.

But growing U.S. involvement in the war — through billions of dollars in weapons and intelligence-sharing — could foster a greater risk of a humiliated and desperate Vladimir Putin lashing out.

• Director of National Intelligence Avril Haines testified Tuesday the Russian president would likely only use nuclear weapons "if he perceived an existential threat to the Russian state or regime."
• "We're supporting Ukraine, but we also don't want to ultimately end up in World War III, and we don't want to have a situation in which actors are using nuclear weapons," Haines told the Senate Armed Services Committee.

Between the lines: "One of the difficulties of this situation is that the better the Ukrainians do, the more dangerous Putin is," Sen. Angus King (I-Maine), a member of the Senate Armed Services and Intelligence committees, told Axios.

• The maximalist demands Putin set at the beginning of the war are making it difficult for him to find a way to back down.
• King believes it's up to the Ukrainians — not the U.S. — to determine the end game.
• "They believe they can win. And so I think it would be difficult for President [Volodymyr] Zelensky to make significant concessions to Putin because of the mood in Ukraine," King said.

Behind the scenes: Ukraine's ambassador to the U.S., Oksana Markarova, addressed both the Senate Democratic and Republican lunches on Tuesday, a day after a deal was reached on the new aid package.

• She told senators Ukraine needs enough firepower to regain its sovereignty, Sen. Kevin Cramer (R-N.D.) told Axios. In other words, push Russian forces out every inch of Ukrainian territory — including Crimea and areas of the Donbas region that have been occupied since 2014.
• "It seemed to me that she's very optimistic about that if they get what they need in this next package," Cramer said. "Clearly, their goal is to win and to get all of their land territory back."

Asked if that was a realistic scenario, Cramer replied: "Listen, I didn't think it was realistic that they'd be where they are, so we've been underestimating them and overestimating Russia since the beginning of this."

• "I think people are learning their lesson."

What to watch: Sen. Richard Blumenthal (D-Conn.) told Axios he's pushing to add a resolution to the Ukraine package urging the Biden administration to designate Russia a "state sponsor of terrorism."

• If the resolution is ultimately brought to the Senate floor alone, both Blumenthal and his co-sponsor, Sen. Lindsey Graham (R-S.C), predicted it would receive over 90 votes.