This is not quite as good as getting the Mexicans to pay for the fence, but it is not a bad start. Little Donny, b/k/a President Donald Trump, can order the building of his big fence because, in part, congressional democrats voted to authorize it, from Daily Caller [1]:
President Donald Trump will be able to order the construction of a wall on the Mexico border Wednesday with the stroke of a pen, because of a 2006 law passed with the help of Democrats including Barack Obama, Joe Biden and Hillary Clinton.
The 2006 law authorized the construction of 700 miles of fencing along the southern border, as well as additional lights, cameras and sensors to enhance security. Although former President George W. Bush signed the measure into law, the Democrat-controlled Congress that took over a few months later ensured it would never be completed by means of an amendment to a 2008 spending bill.
Too smart by half