MUSCATINE — Eastern Iowa is home to industrial riverfront cities, small towns surrounded by farmland and a consequential number of voters who were inspired to vote for both Barack Obama and then Donald Trump.And unlike many of the president’s Republican supporters, who could never imagine voting for a Democrat, many of these Obama-Trump voters are open to doing just that — meaning that Iowa counties along or near the Mississippi River, and similar ones throughout the Midwest, could be key to determining the next president.“I voted for Trump — still not sure if it was the right decision,” said Tammy Faulkner, 48, a convenience store clerk who lives in Louisa County in southeast Iowa and who voted for Obama in both 2008 and 2012.