Katie Packer, the Republican operative leading the anti-Donald Trump super PAC, pitched her strategy to stop the Republican front-runner on a call with more than 50 GOP donors and power brokers Tuesday, including those with ties to the campaigns of Marco Rubio, Jeb Bush, Scott Walker and Chris Christie…

Packer, a veteran of Mitt Romney’s 2012 campaign who launched Our Principles PAC, told CNN that “it concerns me” that Super Tuesday’s results might not make her task any easier by knocking any Republicans out of the field.

But, she added, “if the worst-case scenario is we have to take it all the way to the convention, that’s fine by me.”…

Packer argued that Trump has not faced a sustained negative advertising campaign. She pointed out that so far, of the $215 million spent on the air in the GOP race, only $9 million has been funneled into attack ads against Trump — less than the $10 million Romney’s campaign spent in a single week in a single state, Florida, to undercut Newt Gingrich in 2012.

“The reality is that there has been no sustained campaign against this guy until last Thursday,” she said.