Its personal with McCain & Graham.
Hagel realized Iraq was a bad mistake. McCain was gun-ho for Iraq & the surge.
Even though Hagel campaigned with McCain when he was running against GWB, he didn't come out & support him when he ran against Obama. He probably voted for Obama. And Hagel's wife came out & supported Obama.
So, McCain has a hard on for Hagel & we know how resentful he still is for losing to Obama...