US President Donald Trump's pick to be the next senator from Alabama crashed to defeat Tuesday against a populist former judge in a runoff election likely to send shock waves through establishment Washington.

With just over half of precincts reporting, Fox News, CNN and other news outlets called the race for former Alabama state chief justice Roy Moore, who was leading incumbent Luther Strange by 56.7 percent to 43.3 percent.

Strange was appointed to the US Senate earlier this year to fill the seat vacated by Jeff Sessions, whom Trump picked to be his attorney general.