By Erin Murphy, Gazette-Lee Des Moines BureauDES MOINES — Vice President Mike Pence and U.S. Sen. Joni Ernst stood on stage together Thursday, waving to supporters with the Iowa Senate and presidential races in a dead heat heading into Election Day.“Four years ago you believed we could be strong again, you believed we could be prosperous again,” Pence told a crowd of roughly 200 people gathered at the Des Moines airport on a cool and windy afternoon.