Sen. Bernie Sanders gave a speech on the Senate floor Thursday expressing grave concern over the "drumbeats" of war building in Washington, D.C., amid escalating tensions along the Ukrainian border.
Sanders, I-Vt., the de-facto leader of the Democratic Party's progressive wing, which had kept relatively quiet on the issue to this point, pleaded with government officials to not follow a similar path of past military conflicts.
"I'm extremely concerned when I hear the familiar drumbeats in Washington, the bellicose rhetoric that gets amplified before every war, demanding that we must 'show strength,' 'get tough' and not engage in 'appeasement'," said Sanders, who has, in the past, led the charge to defund the war in Iraq and to withdraw U.S. troops from Afghanistan.
The senator focused on the "unintended consequences" that have resulted from previous American military involvements and the way wars have been portrayed in the lead up to those conflicts.
"They [wars] rarely turn out the way the planners and experts tell us they will. Just ask the officials who provided rosy scenarios for the wars in Vietnam, Afghanistan and Iraq, only to be proven horribly wrong," Sanders said.
Sanders reaffirmed his support for the pursuit of a diplomatic solution with Russia, the latest attempts of which have been led by French President Emmanuel Macron, who met with Russian President Vladimir Putin and Ukrainian President Volodymyr Zelenskyy separately this week.
While condemning Putin over his responsibility for the current crisis, Sanders also called on officials to "consider the perspectives of our adversaries." Putin has demanded the U.S. and Europeans commit to keeping Ukraine out of NATO, something the West has rejected outright.
"One of the precipitating factors of this crisis, at least from Russia's perspective, is the prospect of an enhanced security relationship between Ukraine and the United States and Western Europe," Sanders said.
In addition to his war critique, Sanders objected to potential sanctions against Russia and the possible impact on civilians. That includes a package the Senate has been discussing that could cause economic devastation in Russia and reverberate across Europe.
The legislation appears to be on hold following disagreement on a variety of issues, including the strength of the sanctions, leading some to suggest President Joe Biden should proceed on his own.
On Tuesday, Senate Minority Leader Mitch McConnell, R-Ky., indicated it would be better for Biden to take action as opposed to waiting for the passage of a sanctions package he believes wouldn't deter Putin. Sen. Richard Blumenthal, D-Conn., struck a similar tone.
"We're just a hair's breadth away from an agreement on strong, message-sending sanctions legislation, but I really believe the Biden administration should act now -- in fact yesterday," said Blumenthal, a member of the Senate Armed Services Committee.
Concerns about a Russian invasion into Ukraine continue to build as the Russian military began a series of exercises in Belarus on Thursday that are expected to continue until Feb. 20.
"[We] must work hard to achieve a realistic and mutually agreeable resolution...that is not weakness," Sanders said. "That is not appeasement. Bringing people together to resolve conflicts nonviolently is strength, and it is the right thing to do."
ABC News' Trish Turner and Allison Pecorin contributed to this report.