President Biden's weak and unreliable leadership abilities have led to a void in certain aspects of world affairs, retired Lt. Gen. Keith Kellogg said in an interview airing Sunday on "Life, Liberty & Levin".

Kellogg, who served as Vice President Michael Pence's national security adviser and is a Fox News contributor, told host Mark Levin that while Ukrainian President Volodymyr Zelenskyy has shown courage and leadership in defending his land against Vladimir Putin's military, the discussions of potential "diplomatic off-ramps" for the ex-KGB agent are noticeably lacking the Americans.

Newly-minted German Chancellor Olaf Scholz and French President Emmanuel Macron have both been on the front lines of seeking a diplomatic end to the conflict, with Macron often acting as a quasi-representative for the West in engaging with the Kremlin.

(Gen. Keith Kellogg, Ret.)

"Here's the one thing that concerns me right now, because there's always a diplomatic off-ramp to any conflict," Kellogg said. 

"You'll notice that everybody is talking to President Macron of France or Olaf Scholz of Germany, or they're talking to others around the world. They're not talking to the United States."

Last month, Macron engaged Putin in a 5-hour meeting at the Kremlin in Moscow.

"Why are they not talking to the United States?" Kellogg asked Levin. "We're sitting… on the backbench, sitting, watching what's happening because they don't have any trust or belief that this President Biden can pull it off."

In parliamentary parlance, a "backbencher" is used to describe a low-ranking MP or former member of leadership or a "shadow cabinet" who no longer has much legislative pull in-session.

"I guarantee you they'd be talking to President Trump. I guarantee you President Trump would have been front and center," the retired general added.

Additionally, Kellogg warned of the Americans' explicit fear of provoking a Russian escalation if they interfere or intercede on the part of Ukraine.

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French President Emmanuel Macron talks to journalists Tuesday June 8, 2021 at the Hospitality school in Tain-l'Hermitage, France (Philippe Desmazes, Pool via AP)

French President Emmanuel Macron talks to journalists Tuesday June 8, 2021 at the Hospitality school in Tain-l'Hermitage, France (Philippe Desmazes, Pool via AP)

"What it comes down to, very candidly, is intestinal fortitude, the ability to have guts to make a hard decision instead of wringing your hands in a negative manner," he said.

"And we're very concerned about escalation. Look, the guy who's escalated is Vladimir Putin. That's the one who started the war. That's the one who's pushed himself into Ukraine. That's the one who has put the civilian population at enormous risk. He's actually conducting war crimes."

"If you're afraid of the other guy, and you're afraid of escalation, then you'll probably be in the wrong business being a leader. And we should push back on them," Kellogg added, noting Putin has several "vulnerabilities" despite his reputation.

"He doesn't bluff, and we shouldn't bluff either."