(NewsNation) — Despite billions in U.S. aid, the war in Ukraine is unlikely to end soon, Director of National Intelligence Avril Haines said at a Senate hearing Thursday.

Retired four-star general and former NATO Supreme Allied Commander Wesley Clark joined “The Hill on NewsNation” and said that even without assurances of a quick victory, the war in Ukraine is in the best interests of the U.S.

“What you got here is a critical situation that affects global security,” said Clark. “Were Ukraine to collapse, we’d be faced with a huge national security crisis in Europe. And it would empower the Chinese to go after Taiwan.”

Haines told the Senate Armed Services Committee on Thursday that Russia has intensified strikes on Ukraine’s infrastructure to hamper Kyiv’s ability to move arms and troops, slow defense production and force it to consider negotiations.

Clark went as far as to say that given the importance of defeating Russia, a timetable for either a Russian or Ukrainian victory is impossible.

“I don’t think you can look at it in terms of a time play,” he said.

The former general said he’s predicting more violence heading into the summer.

“You’re going to see Russia try to make a big play here in the next month and a half to try to grab as much terrain as it can,” said Clark. “(Russia) may make a new assault on Kyiv. It’s going to be a hair-raising time in Ukraine and for the West.”