The alarms are growing louder about the Ukraine crisis — and questions are becoming sharper as to how the issue will reverberate through American domestic politics.

A full-scale Russian invasion would pitch President Biden into new turmoil. The failure to prevent such a move would be regarded as a diplomatic failure by the White House. It would be another foreign policy misstep to add to the chaotic withdrawal from Afghanistan last year.

But Republicans are also divided on Ukraine, with some the most pro-Trump elements of the GOP voicing isolationist sentiments. Their views complicate the GOP’s traditional hawkish image.

Biden has ruled out directly involving U.S. troops in a ground war in Ukraine, even in the event of a Russian invasion. And he has the challenge of keeping NATO allies on the same page if Russian President Vladimir Putin mounts some kind of aggressive operation that stops short of a traditional, full-on military assault.

In alluding to this conundrum at a recent press conference, Biden appeared to suggest that Putin could get away with a “minor incursion” — a statement that infuriated the Ukrainians and the White House tried to clean up, with limited success.

The messy domestic picture stands against a stark reality — expectations are rising that Putin will press ahead in some shape or form.

At a Pentagon briefing on Friday, Secretary of Defense Lloyd Austin and Gen. Mark Milley, the chairman of the Joint Chiefs of Staff, said that Putin had assembled all he needed for a full-scale invasion of Ukraine. The Russians are now estimated to have more than 100,000 troops adjacent to the border.

Milley told reporters that “you’d have to go back quite a while to the Cold War days to see something of this magnitude.”

The comment echoed Biden’s remark last week that a Russian invasion would “change the world” and would, in practical terms, be “the largest invasion since World War II.”

But one pressing political question is whether Biden will play a political price at home for a failure of diplomacy if Putin presses ahead.

Robert Wilkie, a former secretary of Veterans Affairs and, before that, an under secretary of Defense during the Trump administration, faulted the Biden administration, saying that “we haven’t been playing the long game while Putin has.”

Wilkie, who was also assistant secretary of Defense under former President George W. Bush and is now a visiting fellow at the conservative Heritage Foundation, argued that there were longer-term moves the administration could make to constrain Putin, such as “opening up an avenue for Finland and Sweden to come into the NATO family” to help change the overall dynamic in Europe.

But he also noted there were real difficulties, not least Russia’s increasing closeness with China, which he argued made sanctions less likely to be effective. 

“Unlike in the past, Putin has a banker now — and that’s Beijing,” he said.

Liberal voices are of course more supportive of Biden’s position, arguing that he has played his hand as well as he could, including making clear to Putin that there will be severe consequences for an invasion.

“The U.S. does have a number of tools that it can use that would be really painful for the Kremlin and potentially catastrophic for Russia overall,” said Max Bergmann, a senior fellow and the director for Europe and Russia at the liberal Center for American Progress.

But Bergmann added, “We should not think of this as a way to find a silver bullet that will cause Vladimir Putin to not invade or to say, ‘Uncle.’” He argued Putin had painted himself into a corner with his troop buildup and would have to go ahead with some form of action at risk of losing face.

Russia denies it has any intention of invading Ukraine, assurances that are dismissed in Washington because of the troop movements. The Kremlin wants a formal commitment that Ukraine, which is not a NATO member, will never be allowed to join the alliance. But that kind of guarantee is a non-starter with the U.S. and other Western nations.

Complicating the political calculus at home are the Trump Republicans. 

Rep. Paul Gosar (R-Ariz.) has contended that “we have no dog in the Ukraine fight.” A recent story from Axios noted the influence of Fox News broadcaster Tucker Carlson, who has been openly skeptical about the need for the U.S. to get involved on Ukraine’s side. The website also noted a number of GOP candidates who have sounded similar themes.

Those positions sit very uneasily with the GOP’s traditional hawkish image. They also draw scorn from liberal foreign policy experts, who accuse Trump Republicans of giving comfort to an adversary.

“Protest is fine, disagreement on policy is fine, but active support for Putin’s expansionist policies, including the potential invasion of another democracy, give confidence to Putin that he has effectively undermined the American president at home,” said Joel Rubin, a former deputy assistant secretary of State during the Obama administration.

Some polling shows the peculiar contours of U.S. public opinion in relation to Ukraine. An Economist-YouGov poll released last week, for example, indicated more Republican voters than Democratic voters consider Putin a “strong leader.” 

Asked whether it was more important for Washington to “take a strong stand” on Ukraine or “maintain good relations with Russia,” voters of both parties went for the first option. But Republicans did so by a slimmer net margin (32 percentage points) than their Democratic counterparts (44 percentage points).

There is, too, the fact that American voters have a raft of other, more immediate topics to worry about, with COVID-19 and inflation prime among them.

That could mean that another blow to American prestige in the shape of a Russian invasion would hurt Biden anew. Or it could mean that U.S. voters simply don’t care all that much what happens in Kyiv.

Right now, it’s a waiting game that is becoming more tense by the day. The most likely time for a Russian invasion is in the next few weeks as the ground freezes and makes troop movements easier.

“I think [Putin] is going to do it,” said Bergmann. “Once you put this in motion, it can be hard to unwind it without losing face and credibility. ... He could just leave forces where they are. But, yeah, I would be nervous.”

The Memo is a reported column by Niall Stanage.