The announced policy of the current administration is that the United States will maintain and replace its nuclear “capabilities” as necessary but will not develop whole new capabilities. The follow-ons to the Minuteman III and the ALCM fall squarely within the bounds of that policy. In particular, the LRSO is simply a cruise missile that (1) will keep the nation’s long-range standoff nuclear — and conventional — capabilities operational for the future, as we finally let the ancient ALCM/CALCM go off to its rest; and (2) will actually be able to do what a cruise missile is supposed to do: enemy survive air defense systems and get to its target. (The ALCM/CALCM has been obsolete, in terms of surviving the best integrated air defense systems, for at least a decade.)
As for the argument that since the U.S. will have the modernized B-61 bomb (modernized in a program that was opposed by the same people who are opposing the LRSO now, incidentally) it doesn’t need a standoff nuclear capability…um, I don’t think you quite understand the rationale for having standoff weapons in general. Having a weapon like LRSO allows you to take a 1960’s-era B52 or an 1980’s-era B1 and keep it relevant option for delivery weapons against countries that have modern air defenses; they can usefully take on nuclear deterrence and other roles so you can largely keep your stealth bombers, the B2 and the future B21, free for other things. Like penetrating strike. Plus, one B52 armed with 20 long-range cruise missiles can hit a lot more targets on one mission than any one penetrating aircraft that needs to go all the way to the target can.
Penetrating strike has it uses. Standoff strike has its uses. They’re aren’t interchangable capabilities. Whether you’re talking about the conventional side of things or the nuclear side of things. And one should certainly take note of the fact that our potential adversaries in the event of either major conventional or (god forbid) nuclear conflict understand this well: across the board they are upgrading their cruise missiles and developing new ones, conventional and nuclear.
One final thing: we are, in any case, desperately going to need a conventional LRSO (or something very similar to it) to counter continuing Russian and Chinese air defense improvements over the coming decades. (The U.S. has exactly zero other air-launched weapons current planned for the foreseeable future with a range over 500 miles.) And while you’re buying conventional version, might as well spend a relatively little bit extra to keep a very valuable — for deterrence purposes — nuclear capability around as well.