President Biden will seek a five-year extension of the New START nuclear arms control pact with Russia before it expires on Feb. 5, senior officials told the Washington Post.

Why it matters: The 2010 treaty is the last remaining constraint on the arsenals of the world's two nuclear superpowers, limiting the number of deployed nuclear warheads and the bombers, missiles and submarines which can deliver them.

• Russia has already expressed support for five-year extension — a simple process that only requires an exchange of diplomatic notes.
• Biden has long supported an extension, but his administration hadn't previously committed to the five-year timeframe.

The other side: The Trump administration was skeptical of New START, arguing that it had allowed Russia to build up advanced nuclear systems that aren't constrained by the treaty.

• Trump's arms control envoy, Marshall Billingslea, had also insisted that China be brought into the arms control process.
• Billingslea attempted to negotiate a shorter-term extension of New START, paired with a freeze on all nuclear warheads and a commitment to broaden future talks to include other nuclear powers. That deal never came together.

The big picture: The Biden administration arguesthat the U.S. is better off pursuing discussions on the future of arms control — and confrontation with Russia on other issues — with the New START guardrails in place.

• Officials told the Post that Biden is ruling out a "reset" with Russia, which the Obama administration had initially opted for, in light of the Kremlin's "reckless and aggressive actions" in recent years.
• The officials said Biden will ask newly confirmed Director of National Intelligence Avril Haines to provide him with full intelligence assessments on Russia's alleged interference in the 2020 election, poisoning of opposition leader Alexey Navalny, bounties on U.S. troops in Afghanistan, and hacking of federal agencies.