CEDAR RAPIDS — Sen. Tom Harkin would like to direct more money into the private sector and create jobs by raising the federal gas tax for the first time in 21 years, but he would settle for a stopgap measure to keep highway funds flowing to states.With prospects for a long-term extension of the Highway Trust Fund — at least five years so states could plan their highway and bridge projects — looking unlikely before Congress leaves Washington for its monthlong summer recess, the Iowa Democrat seemed resigned to a short-term fix to avoid disruption.