Perry said Kentucky race and midterms are "inextricably intertwined" with country's future.
Sen. Shaheen asked Brown to sign a pact limiting outside campaign spending.
“The race is close. It will be close," a Michigan pollster said.
Shaheen hopes to limit outside, third-party spending in Senate race.
Other S.C. primary opponents flinched at the comment.
Brown is seen as GOP's best shot at unseating Democratic Sen. Jeanne Shaheen.
A new ad from the Democratic Senate Majority PAC hits Rep. Bill Cassidy (R-La.), Sen. Mary Landrieu’s (D-La.) main Republican opponent, for his support from Koch Brothers-backed groups.
She calls Sasse the “clear conservative choice” in the GOP primary for the open seat.
The Democrat has a double-digit lead over his GOP opponents in the open seat race.
Americans for Prosperity blames the Arkansas Democrat for "if you like it, you can keep it."