As U.S. officials weigh a response to Russias potential invasion of Ukraine, one faction with more influence than ever before is the progressive foreign policy community, which has become increasingly sophisticated and united in trying to both avoid war and overhaul American policies abroad.

In recent days, Democratic Reps. Ilhan Omar (Minn.), Pramila Jayapal (Wash.) and Barbara Lee (Calif.) and their ally Sen. Bernie Sanders (I-Vt.) have warned Washington not to flood the region with weapons and challenged top Democrats who are negotiating with Republicans on sanctions that would hurt Moscow and possibly U.S. allies in Europe. They say the U.S. should bolster Ukraines independence and remain wary of Russian President Vladimir Putin while taking steps to address Russias demand that the country stay out of the NATO military alliance.

The foundation of their response to the Ukraine crisis is that war is not an option. That guiding principle differentiates them from other lawmakers who recommend more aggressive policies like rapidly shipping arms to the Ukrainians while saying little about how that could worsen a possible war or draw in the U.S. Its also a position that emphasizes diplomacy without promoting Putins agenda, defying the long-standing critique that the left is naive about Americas adversaries.

I am under no illusions about the horrors an invasion will unleash, or that it is Russia that is responsible for bringing us to the brink, Omar said in a Feb. 2 statement. Writing in The Guardian, Sanders endorsed severe consequences on Putin and his associates if he does not change course.

A nuanced message on Ukraine is vital for progressives as they expand their influence in Congress and the broader Democratic Party, an aide to a liberal lawmaker told HuffPost. They have won visibility and, under Biden, appointments at the White House, State Department and Pentagon. Now they have to show how they will use that influence to reform a national security state they have long criticized.

By highlighting the risk of ratcheting up tensions with Russia, progressives hope to counter what Sanders described as the familiar drumbeats in Washington, the bellicose rhetoric that gets amplified before every war.

That work is especially important because many Democrats have come to intensely dislike Putin and support harsh measures against him over his ties to former President Donald Trump.

Some people on the left, like Rachel Maddow ... pretty much accept the Cold War analysis of Russia, said Rochelle Ruthchild, a Russian history researcher who is associated with Harvard and Brandeis universities. A number of people who consider themselves to be progressive have very negative attitudes towards Russia.

Though she sees Putin as a vile leader, Ruthchild says the U.S. should engage with his concerns over Ukraines military ties with the West, noting that some other nations near Russias borders have committed to neutrality and that Washington has had its own problems over its neighbors drawing close to its rivals.

If the Mexicans voted to create some sort of alliance with Russia, how would we be reacting? she asked.

To hold to their values and show an evolution beyond hard left thinking that has historically been pro-Moscow, progressives can make their case without denying Ukrainian independence or human rights or suggesting that world politics is only up to major powers like the U.S. and Russia.

The left needs to stand in solidarity with a democratic Ukraine, Ruthchild said.

The progressive position broadly aligns with the Biden administrations approach of urging negotiations and de-escalation, consulting with European partners while sending them troop reinforcements and emphasizing that the U.S. does not want a war with Russia over Ukraine.

On Tuesday, leading progressives said they back the presidents approach.

The president has surprised Russia by strengthening our alliance with our European allies and making clear that the costs of invasion will be very high with Russia, Sen. Elizabeth Warren (D-Mass.) told HuffPost. Sen. Jeff Merkley (D-Ore.) said Biden is using the right strategy, and Sanders told NPR the administration is doing its best walking a very difficult tightrope.

Together, Democrats clearly contrast with Republicans. While some conservatives are claiming the anti-war mantle, they are doing so by attacking Ukrainians , as has Fox News host Tucker Carlson, or by pushing policies that could lead to a greater confrontation, as has Sen. Josh Hawley (R-Mo.), who wants to reject any NATO membership for Ukraine but also drastically increase military spending by NATO members.

Most in the GOP are promoting the partys traditional hawkishness. Sen. Jim Risch (Idaho) indicated Tuesday that he wants to pursue tougher sanctions than those centrist Democrats would accept, and Sen. Ted Cruz (Texas) has portrayed the crisis as the result not of Putins escalation but of Bidens weakness.

Instead of being spooked by conservative complaints and looking over their right shoulder, Bidens team could use the progressive movement to stop dumb stuff and do good stuff, the liberal aide said.

The progressive stance also aligns with some experts on the region.

Fiona Hill, a widely respected former White House official, recently wrote that she warned the U.S. of Putins sensitivities around Ukraine and NATO. She sees the best American course of action now as rallying international opposition to Russias bullying of Ukraine and keeping European allies close (rather than trying to bash partners like Germany as some Republicans have suggested).

In a phone interview from Kyiv, analyst Hlib Vyshlinsky of the Centre for Economic Strategy think tank said Americas policy must include more than threats of sanctions following a possible Russian attack.

Because Moscow has shored up its foreign reserves in gold rather than U.S. dollars, they have a stock of resources that will help them adjust, at least in the short term, Vyshlinsky, the centers executive director, told HuffPost.

He understands that different elements of the left have competing views of the U.S. vision of global order and institutions that Ukraine has worked with like NATO and the International Monetary Fund. But he added, If you are a liberal person who believes in freedom, human rights, democracies and equal opportunity ... then there is no other option than supporting Ukraine.