Republican presidential candidate John Kasich on Wednesday questioned if rival Jeb Bush should carry on his campaign if it relies only on negative attack ads.

“I think it’s a sad situation when you’ve got to rely on negative to move voters, which they haven’t been able to do, as opposed to articulating a positive vision. Why don’t do they do that?” Kasich said on ABC’s “Good Morning America” Wednesday morning, referring to an internal Bush memo that circulated late Tuesday evening attacking the Ohio governor’s chances in South Carolina.