AP Photo/Carolyn KasterThe White House press secretary, Sarah Huckabee Sanders, on Thursday repeatedly dodged questions about President Donald Trump's threat to shut down the government over funding for his proposed wall along the US-Mexico border. Though Trump often promised during the campaign that Mexico would pay for a wall, he has since turned his attention to the Republican-controlled Congress to fund the project, which Senate Democrats contend would cost $70 billion to build and $150 million a year to maintain. At a rally in Arizona on Tuesday, Trump said, "If we have to close down our government, we're building that wall." During her first press conference in three weeks, Sanders refused to answer four questions about whether Trump would refuse to sign a bill funding the federal government if money for a border wall were not included. "The president promised over and over again during the campaign that Mexico would pay for the wall," ABC News' Jon Karl said.