Dick Lugar: “Modernization and replacement of strategic offensive arms may be carried out.”

The President has to want to get back into the discussions. At this point, there is not evidence that that is the case.

It seems to me to be really a safety net there.

In the likely event the INF Treaty collapses in August, the only remaining bilateral U.S.-Russia arms control agreement would be New START, which expires in 2021 but can be extended by up to five years through agreement by both parties.

Several members of Congress have already proposed legislation along these lines.