"I love working for the people of Indiana, I love helping our citizens make the most of their lives, but I do not love Congress," Bayh said during a news conference in Indianapolis. "I will not, therefore, be a candidate for election to the Senate this November."
For some time, he said, "I have had a growing conviction that Congress is not operating as it should," with too much partisanship and narrow-mindedness and too little progress and problem-solving.
"Even at a time of enormous challenge, the peoples' business is not being done," said Bayh, a former governor and secretary of state in Indiana.
Two recent examples of partisan gamesmanship galvanized his decision, he said.
"Two weeks ago, the Senate voted down a bipartisan commission to deal with one of the greatest threats facing our nation: our exploding deficits and debt. The measure would have passed, but seven members who had endorsed the idea instead voted 'no' for short-term political reasons," Bayh said. "Just last week, a major piece of legislation to create jobs ... fell apart amid complaints from both the left and right."
"All of this and much more has led me to believe that there are better ways to serve my fellow citizens, my beloved state, and our nation than continued service in Congress," he said.
U.S. President Barack Obama praised Bayh's 20-plus years serving the Hoosier State.
"During that time, he has fought tirelessly for Indiana's working families, reaching across the aisle on issues ranging from job creation and economic growth to fiscal responsibility and national security," Obama said in a statement.
Notable deaths of 2014 [PHOTOS]