A currency trader walks by the screen showing the Korea Composite Stock Price Index (KOSPI) at the foreign exchange dealing room in Seoul, South Korea, Tuesday, Dec. 18, 2018. Asian stocks fell on Tuesday, tracking losses on Wall Street as traders braced for an interest rate hike by Federal Reserve. (AP Photo/Lee Jin-man)

FILE - In this Nov. 30, 2018 file photo, U.S. Border Patrol detain Honduran migrants after they walked onto U.S. territory from Tijuana, Mexico. Federal judges in California have challenged more of the Trump administration's "zero-tolerance" policy on illegal immigration. Their decision in Sept. 2018 to no longer accept pleas at initial appearances led to the dismissal of many cases because the government deported defendants before they could return to court. The judges' stance is another example of how the judiciary, in ways large and small, has put the brakes on some of the administration's efforts to curb immigration. (AP Photo/Felix Marquez, File)

A currency trader walks by the screen showing the Korea Composite Stock Price Index (KOSPI) at the foreign exchange dealing room in Seoul, South Korea, Tuesday, Dec. 18, 2018. Asian stocks fell on Tuesday, tracking losses on Wall Street as traders braced for an interest rate hike by Federal Reserve. (AP Photo/Lee Jin-man)

FILE - In this July 2, 2015 file photo, Russian metals magnate Oleg Deripaska attends Independence Day celebrations at Spaso House, the residence of the American Ambassador, in Moscow, Russia. A day after the World Economic Forum said it will include a Russian delegation at the forum, Kremlin spokesman Dmitry Peskov on Monday Dec. 17, 2018, welcomed the announcement that billionaires Oleg Deripaska and Viktor Vekselberg, and the head of the state-controlled bank VTB Andrei Kostin, will be able to attend the annual gathering in the Swiss ski resort of Davos in January. (AP Photo/Alexander Zemlianichenko, File)

Heads of the delegations react at the end of the final session of the COP24 summit on climate change in Katowice, Poland, Saturday, Dec. 15, 2018.(AP Photo/Czarek Sokolowski)

FILE - This Oct. 23, 2018 file photo shows HealthCare.gov website on a computer screen in New York. A federal judge's ruling that the Obama health law is unconstitutional has landed like a stink bomb among Republicans, who've seen the politics of health care flip as Americans increasingly value the overhaul's core parts, including protections for pre-existing medical conditions and Medicaid for more low-income people. (AP Photo/Patrick Sison)

In this Monday, Dec. 10, 2018 photo toxic froth from industrial pollution floats on Bellundur Lake in Bangalore, India. As politicians haggle at a U.N. climate conference in Poland over ways to limit global warming, the industries and machines powering our modern world keep spewing their pollution into the air and water. The fossil fuels extracted from beneath the earth's crust _ coal, oil and gas _ are transformed into the carbon dioxide that is now heating the earth faster than scientists had expected even a few years ago. (AP Photo/Aijaz Rahi)