The primary winner will take on Republican Pat Toomey for his spot in the Senate.
The largest federal employee union is throwing its support behind the congressman.
Kirk said he was "leading by example" by meeting with Merrick Garland.
Sen. Moran faced conservative backlash after he voiced support for a hearing for Obama's pick.
The ad attacks the senator for her opposition to holding a hearing for Obama's SCOTUS nominee.
Sen. Mark Kirk quickly broke with his party's Supreme Court strategy.
Republican Jerry Moran said the Senate should hold a hearing for Obama’s nominee.
Ron Johnson and Mark Kirk targeted their election opponents.
Sen. Pat Toomey stressed he hasn't changed his mind about leaving the seat vacant.
Sharron Angle’s entry into the Nevada Senate race creates a headache for Republicans.