Republican presidential candidate Donald Trump continued his ongoing feud with Sen. Jeff Flake (R-AZ) on Sunday night, calling the senator "very weak and ineffective" as well as "sad."

Flake has made it no secret about his feelings regarding Trump. He lead the charge against his party's convention and spent this Sunday slamming Trump on CBS's "Face the Nation."

Flake said that he's annoyed with Trump’s tendency to jump from message to message when it comes to immigration policies. He claimed it confuses voters.

“It’s kind of a 360-degree pivot at times. That’s not clear at all. Some people said it was hardening, some said softening. I say it was just confusing,” Flake told host John Dickerson.

Flake continued, saying that the ordeal makes it increasingly unlikely he'll ever support Trump's candidacy.

“It becomes increasingly difficult to see that he’s going to change, so I don’t expect that I’ll be able to support him in November,” he said.

Trump responded with another of his famous uncensored Twitter wars:

Mocking Trump's tendency to engage in a full on attack of anyone who comes close to slighting him, Clinton ridiculed Trump on Twitter as well.

Given that the United States Constitution puts Congress in charge of making the laws, anyone in the executive branch is forced to work with Congress to achieve anything in their agenda. After attacking everyone from House Speaker Paul Ryan, Flake as well as senior Arizona Senator John McCain and being slammed by others who have denounced Trump, Clinton isn't far off base.