More N-power:The ‘nuclear football’, which always travels with the U.S. President for use in a nuclear attack.NY TimesDOUG MILLS  

A treaty committing the U.S. and Russia to keep their long-range nuclear arsenals at the lowest levels since early in the Cold War went into full effect on Monday. When it was signed eight years ago, President Barack Obama expressed hope that it would be a small first step toward deeper reductions, and ultimately a world without nuclear weapons.

Now, that optimism has been reversed. A new nuclear policy issued by the Trump administration on Friday, which vows to counter a rush by the Russians to modernise their forces even while staying within the treaty limits, is touching off a new kind of nuclear arms race. This one is based less on numbers of weapons and more on novel tactics and technologies, meant to outwit and outmanoeuvre the other side.

The Pentagon envisions a new age in which nuclear weapons are back in a big way — its strategy bristles with plans for new low-yield nuclear weapons that advocates say are needed to match Russian advances and critics warn will be too tempting for a President to use. The result is that the nuclear-arms limits that went into effect on Monday now look more like the final stop after three decades of reductions than a way station to further cuts.

Yet, when President Donald Trump called on Congress to “modernise and rebuild our nuclear arsenal” in his State of the Union address last week, he did not mention his administration’s rationale: that President Vladimir Putin of Russia has accelerated a dangerous game that the United States must match, even if the price tag soars above $1.2 trillion.

In contrast to Mr. Trump’s address, the report issued on Friday, known as the Nuclear Posture Review, focussed intensely on Russia. It described Mr. Putin as forcing the U.S.’s hand to rebuild the nuclear force.

The report contains a sharp warning about a new Russian-made autonomous nuclear torpedo that appears designed to cross the Pacific undetected and release a deadly cloud of radioactivity that would leave large parts of the West Coast uninhabitable.

It also explicitly rejects Mr. Obama’s commitment to make nuclear weapons a diminishing part of American defences. The limit on warheads — 1,500 deployable weapons — that went into effect on Monday expires in 2021, and the nuclear review shows no enthusiasm about its chances for renewal.

Even Mr. Trump’s harshest critics concede that the United States must take steps as Russia and China have invested heavily in modernising their forces, making them more lethal.NY Times