Some Republicans say a mailer in support of Senator Richard Lugar encourages Democrats and independents to vote in the Republican primary.
The bill would end six-day mail delivery, close post offices and begin to phase out door-to-door delivery entirely.
Six-term Republican Sen. Dick Lugar of Indiana is facing his first primary challenge since winning the job in the 1970s.
Joe Donnelly says he will invest more in education funding for areas that spur job growth.
Lugar has until April 9th to get a new Indiana address and register to vote.
Indiana's two U.S. Senators voted Wednesday against a federal transportation bill they say would reduce funding to the state.
Indiana is one of 26 states that joined in a lawsuit challenging the federal Affordable Care Act.
The American Postal Workers Union President says Indiana's senators need to pass a bill that will help the U.S. Postal Service balance its budget.
Senator Richard Lugar says his bill could help move the construction of the Keystone XL pipeline forward quickly.
Friday marked the 20th anniversary of the nuclear non-proliferation treaty.