WASHINGTON - President Donald Trump will seek $8.6 billion in his new budget to build the U.S.-Mexico border wall, two administration officials said Sunday, setting up another showdown with Congress, which has resisted giving him more money for his signature campaign promise. The request would more than double the $8.1 billion already available to the president after he declared a national emergency at the border in order to circumvent Congress once lawmakers refused his funding demands. That standoff led to a 35-day partial government shutdown, the longest in U.S. history. The officials confirmed that the request was part of Trump's spending blueprint for the 2020 budget year that begins Oct. 1. That document, which sets the stage for negotiations ahead, proposes boosting defense spending to $750 billion while reducing nondefense accounts by 5 percent, with cuts recommended to safety net programs used by many Americans.