CHICAGO — The filing period for presidential candidates to appear on Illinois’ March 19 primary ballot ended Friday with former New Jersey Gov. Chris Christie putting in paperwork to join the party’s top three national contenders, former President Donald Trump, Florida Gov. Ron DeSantis and former United Nations ambassador Nikki Haley. But Christie’s filing indicated the difficulties of putting together a national campaign organization for the GOP field’s most vocal opponent of Trump. Trump, DeSantis and Haley on Thursday all filed full slates of 51 delegate candidates — three from each of the…
