North Korean missile advances put new stress on US defenses

The Pentagon has spent tens of billions to develop what it calls a limited defense against missiles capable of reaching U.S. soil.

[...] it's unclear whether it has developed the technology and expertise to sufficiently shield such a warhead from the extreme heat experienced when it re-enters Earth's atmosphere enroute to a target.

A Pentagon spokesman, Navy Capt. Jeff Davis, said Wednesday, "We've still not seen a number of things that would indicate a full-up threat," including a demonstrated ability to mate a nuclear warhead to an ICBM.

The Trump administration, like its recent predecessors, has put its money on finding a diplomatic path to halting and reversing North Korea's nuclear program.

An interceptor soars toward its target based on tracking data from radars and other electronic sensors, and is supposed to destroy the target by sheer force of impact outside the Earth's atmosphere.

"The pace of the threat is advancing faster than I think was considered when we did the first ballistic missile defense review back in 2010," Rob Soofer, who is helping review missile defenses, told a Senate Armed Service subcommittee last month.

President Donald Trump's proposed 2018 budget would cut $340 million from missile defense programs intended to deter a potential strike by North Korea, Iran or other countries.