AP reports this afternoon that Arizona Senator John McCain, who facing challenges both from the right (mostly from former state lawmaker Kelli Ward) and the left (Congresswoman Ann Kirkpatrick) as he seeks his sixth Senate term, said that President Barack Obama is "directly responsible" for the Orlando massacre:

Republican Sen. John McCain said Thursday that President Barack Obama is "directly responsible" for the mass shooting in Orlando, Florida, because Obama has allowed the growth of the Islamic State group on his watch.

McCain, who lost to Obama in the 2008 presidential election, made the comment to reporters Thursday while Obama was in Orlando visiting with the families of those killed in Sunday's attack and some of the survivors.

ETA: Kirkpatrick responds:

Elected leaders have a moral duty to work together to root out terrorism and keep Americans safe. But today, we saw John McCain cross a dangerous line in comments that undermine our Commander in Chief on national security issues — at the very moment the president was in Orlando to comfort victims' families. It's difficult to imagine the old John McCain being this reckless with something so serious. John McCain has changed after 33 years in Washington.

ETA: McCain is backtracking from his comments. His official statement says he "misspoke":

I misspoke. I did not mean to imply that the President was personally responsible. I was referring to President Obama’s national security decisions, not the President himself. As I have said, President Obama’s decision to completely withdraw U.S. troops from Iraq in 2011 led to the rise of ISIL. I and others have long warned that the failure of the President’s policy to deny ISIL safe haven would allow the terrorist organization to inspire, plan, direct or conduct attacks on the United States and Europe as they have done in Paris, Brussels, San Bernardino and now Orlando.