Charles Krauthammer told viewers Monday on "Special Report with Bret Baier" that the fight for the Crimean region of Ukraine has basically been lost to Russian president Vladimir Putin, but that the United States must "make it plain that he's got to stop where he is."

"We have no way of getting Putin out of Crimea - he's not going to leave," Krauthammer, a syndicated columnist and Fox News contributor, said. "I think it's likely that in a week or two, it'll be a part of Russia."

"We have to reassure NATO that it's going to stop with Ukraine," he added. "What we should do is to announce that any further step of Putin into the rest of Ukraine, we will immediately, favorably consider requests for weapons and trainers on the ground."

Negotiations with Russia hit a stumbling block on Monday, when Russian foreign minister Sergey Lavrov announced that Russia was not satisfied with the diplomatic proposals that Secretary of State John Kerry presented over the weekend.

According to the State Department, Kerry demanded that Russia halt any further military intervention in Crimea and proposed establishing an international contact group to help resolve the crisis. Lavrov said Russia would be sending its own "counter-proposals" to Washington in the coming days.

Krauthammer laid out possible solutions for President Obama to address himself.

"Number one: order the EPA to consider the 24 pending applications for liquid and natural gas exports, and to expedite and have a verdict within six weeks," Krauthammer said. "And second, call an emergency meeting with Republicans in Congress to re-do the defense budget as a way to increase it, rather than cutting it back. That will be a lesson for the long run, and the Russians will be hurt by it."

The Ukrainian prime minister, meanwhile, will meet with President Obama at the White House on Wednesday to discuss potential paths forward for the embattled nation.