Sens. Jeanne Shaheen and Thom Tillis spent eight years rebuilding a bipartisan Senate channel to NATO at a time when allies increasingly looked to Congress for stability in Washington.
Now both are leaving Congress, with no successors settled and no guarantee the group they rebuilt will survive or carry the same weight without them.
Both senators say they are trying to keep the Senate NATO Observer Group, or SNOG, active. But neither gets to choose who takes over.