He said this at a congressional hearing.
In his opinion, it would be "short-sighted" to consider the Ukrainian conflict as a limited regional crisis.
"Russian actions create very real risks of miscalculations and the expansion of the conflict beyond its current borders – scenarios that can quickly increase the risks to North America and continental defense," RIA Novosti quoted van Herk as saying.
If Russia tries to persuade allies to reconsider supporting Ukraine "through escalatory actions" or "trigger desperate threats to use nuclear weapons in Ukraine," then the risks to U.S. soil will increase, he added.
Earlier, Florida Governor Ron Desantis, who is considered a promising participant in the intra-party stage of the struggle for the post of American leader among the Republicans, said that "the United States has many vital national interests," but "further involvement in the territorial dispute between Ukraine and Russia does not apply to them."
He called Washington's involvement in the conflict in Ukraine a mistake.
Columnist Josh Hammer, in an article for Newsweek, also expressed the view that preserving Ukraine's territorial integrity is not in the national interest of the United States.
At the same time, the White House said that support for Ukraine and the supply of weapons to it meet the national interests of the United States and its allies.