**13. Why did Dayton decide not to run for U.S. Senate re-election in 2006?**
Job offer
Health issues
Disillusionment with D.C.
Lost primary
Answer
Dayton's disillusionment with Washington D.C. politics led him to decide against seeking re-election to the U.S. Senate in 2006. He felt increasingly frustrated by the partisan gridlock and lack of progress in the legislative process.