Once a Foreign Policy Partner, Congress Struggles for Unity on Ukraine

Senators went back to work Tuesday on a legislative response to Russian aggression, but as Congress recedes from the foreign policy arena, bipartisan unity is proving difficult to come by.

WASHINGTON — Since the 1950s, when Senator Arthur Vandenberg declared that “politics stops at the water’s edge,” titans in Congress have been key partners in America’s foreign policy, not as “yes men” to presidents but as co-architects of Pax Americana and the post-World War II order.

But the spiraling Ukraine conflict has pointed up how far the power of Congress in the foreign policy arena has fallen since the death of Senator John McCain, the move of Senator Joseph R. Biden Jr. off Capitol Hill and to the White House, and the rise of a brand of partisanship that extends well beyond the water’s edge.

This week, loud voices emerged urging President Biden to act forcefully to counter Russian aggression. But other lawmakers have used the crisis for partisan advantage, castigating the president and blaming the Biden administration for President Vladimir V. Putin’s assault on his neighbor.