• Russia is a "far more formidable power," but Ukraine's armed forces have improved and are now "combat hardened," said Bradley Bowman, senior director of the Center on Military and Political Power at the Foundation for Defense of Democracies.
• He predicted that Russian forces would ultimately be successful if Moscow chose to invade, but that it would come at a "great cost in casualties."
• A military conflict will likely erode support for the Kremlin, said Andrei Kolesnikov, the chair of the Russian Domestic Politics and Political Institutions Program at the Carnegie Moscow Center.

Russian President Vladimir Putin will have to pay a political price at home if tensions at the border with Ukraine lead to Russian casualties, according to one analyst.

"He's not eager to have Russian forces occupying large portions of Ukraine that are hostile to those forces because he does not want to see casualties coming back to Russia," said Bradley Bowman, senior director of the Center on Military and Political Power at the Foundation for Defense of Democracies.

But even if there's no major combat between the two sides, the Kremlin will have "a spectrum of options" against Ukraine, Bowman told CNBC's "Squawk Box Asia" on Wednesday.

Russia has amassed more than 100,000 troops along its border with neighboring Ukraine, raising alarm that Moscow may be planning to attack. The Kremlin has denied those allegations, but the military build-up has revived memories of Russia's invasion and annexation of Crimea in 2014.

Russia is a "far more formidable power," but Ukraine's armed forces have improved and are now "combat hardened," Bowman said.

He predicted that Russian forces would ultimately be successful if Moscow chose to invade, but that it would come at a "great cost in casualties."

That's going to "have an effect politically on Putin back at home in Russia," he said.

A military conflict will likely erode support for the Kremlin, according to Andrei Kolesnikov, a senior fellow and the chair of the Russian Domestic Politics and Political Institutions Program at the Carnegie Moscow Center.

"Russians are unwilling to bear the price of a war," Kolesnikov said on Twitter.

"If Russia enters a protracted war in Ukraine, it could threaten the broad popular base on which Putin has relied for more than 20 years," he said in an article on Foreign Affairs magazine.

That's something the Russian leader wants to avoid, Bowman said.

"Putin is a shrewd customer, he understands these things. I think he wants to accomplish this objective at the lowest political cost," he added.

'Spectrum of options'

Despite the thousands of troops stationed at the border, a major combat operation is "not necessarily" going to happen between Russia and Ukraine, Bowman said.

Putin would rather achieve his objective — a commitment that Ukraine will not join NATO — at the negotiating table, but that request has been denied by the U.S. and the West, he said.

If Putin can't get that, Russia's playbook includes assassinations, poisonings and coups, he said.

The Kremlin has honed its "gray-zone warfare" of cyberattacks and propaganda, and there is "a spectrum of options" for Putin to use, he added, noting that information warfare is already happening.

Even if Russia attacks, it could choose "punitive missile strikes" without entering Ukraine and occupying new territory, he said.

That said, Moscow could also launch an amphibious assault or annex Ukraine's Donbass region the way it took Crimea in 2014, Bowman added.

He pointed out that both world wars involved the violation of international borders.

"We saw that in Georgia in 2008, we saw in Crimea in 2014 — and we're seeing it now," he said. "We should not take this lightly. This is a big deal."