DFLer Mark Dayton was the last major candidate to step into this year's Senate race. And his announcement last April was met with more than a little skepticism. But Dayton -- a former state auditor and heir to his family's department store wealth -- swept aside three challengers last month to secure the party's nomination for US Senate. His primary victory was due in part to a seemingly constant stream of issue-oriented television advertising paid for out of his own pocket. And a similar strategy has now propelled him ahead of Republican incumbent Rod Grams in recent polls. Minnesota Public Radio's Michael Khoo takes a look at Mark Dayton and his run for the US Senate.