Donald Trump has vowed to "quickly VETO" a bill to reauthorise previously lapsed US national security surveillance measures that he says Obama administration intelligence officials abused to spy on his 2016 campaign.
"Our Country has just suffered through the greatest political crime in its history. The massive abuse of FISA was a big part of it!" the president tweeted, referring to the Foreign Intelligence Surveillance Act that governs a wide swath of US intelligence monitoring operations.
The House is voting on the bill and an accompanying Senate amendment on Wednesday evening after the upper chamber passed both measures last week with overwhelming bipartisan support.
But the president urged House Republicans — who helped put the package together and voted in favour of it months ago — to oppose the bill while Senate committees probe unsubstantiated allegations that the Obama administration intentionally abused the FISA system to unfairly target and undermine the 2016 Trump campaign and incoming Trump administration officials in early 2017 with investigations into their possible connections to Russia.
Mr Trump has referred to this broad theory as "Obamagate."
