Some Republicans and Conservatives Organizing Against Trump

An organized effort by some Republicans and conservatives to stop Donald Trump from securing the party's nomination appears to be taking shape as different groups and former candidates are putting their weight behind other efforts.

A mix of anti-Trump campaign ads, endorsements for Sen. Ted Cruz and talk of a third party candidate are all part of the fight against what many view as inevitable.

Who Is InvolvedA number of Trump's former rivals have joined the cause against the real estate mogul.

The first to make a clear move was former Florida Gov. Jeb Bush, who arranged to meet with Trump's then-rivals Sen. Marco Rubio, Sen. Ted Cruz and Gov. John Kasich ahead of Florida's primary. The specifics about what was discussed during said meetings were never released, but their meetings -- and Trump's lack of one -- was confirmed ahead of the Sunshine State's vote Tuesday.

Rubio subsequently dropped out, and today he told his former supporters in Minnesota that Cruz was the "only conservative left in the race."

Sen. Lindsey Graham, who dropped out in December, is providing a similar show of support to Cruz. Cruz's team confirmed today that Graham will be hosting a fundraiser for the Texas senator on Monday, though he stopped short of giving a full endorsement.

South Carolina Gov. Nikki Haley, who earlier endorsed Rubio, gave a similar nod to Cruz, saying Wednesday that "my hope and my prayer" is that Cruz can "really get to where he needs to go."

"I mean I don't know that I need to formally endorse," she said. "I don't know that that part matters."

Former Republican presidential candidates Mitt Romney and Sen. John McCain have both spoken out against Trump as well.

And there appears to be a grassroots movement taking shape among conservatives.

Blogger Erick Erickson said he participated in a meeting of "grassroots conservative activists from around the country" to discuss ways to beat Trump, who they do not view as a "real conservative candidate."

He didn't share any names of others who attended the meeting, describing the group only as "including supporters of many of the other campaigns."

Rep. Trent Franks, R-Ariz., confirmed the meeting in a statement, but did not detail the discussion.

"My presence at the meeting this morning was primarily to listen. It is certainly no secret that I believe Donald Trump does not represent the best the Republican Party has to offer. His record is anything but Conservative," Franks said today.

How Are They Hitting TrumpThere is more to the anti-Trump effort than just closed-door meetings and endorsements.

The number of groups not affiliated with a specific candidate that have produced anti-Trump ads appears to be growing.

Today the Club for Growth released 30-second television spot in Utah, which has its primary next week, criticizing Trump's previous support for government-run health care.

Trump's comments about women have been the basis of an ad released earlier this week by Our Principles PAC, which is run by former Mitt Romney deputy campaign manager Katie Packer.

By The NumbersMore than $63 million and counting has been spent on anti-Trump ads nationwide, according to an ABC News analysis of data from CMAG/Kantar Media.

Almost half of that money -- $32 million - came from super PACs supporting other Republican presidential candidates. Groups that are purely anti-Trump spent $17.5 million on ads attacking the real estate mogul.

The frequency of the anti-Trump spending has also increased dramatically, with nearly nine times the amount of money that was spent in the first half of February being spent this week alone. That breaks down to $2.53 million being spent each day this week, according to the ABC News analysis of data from CMAG/Kantar Media.

What Solutions Are Being DiscussedThe proposal put forward by the grassroots meeting, Erickson wrote on his news site, The Resurgent, is calling for a "unity ticket" to bring the Republican party together.

"If that unity ticket is unable to get 1,237 delegates prior to the convention, we recognize that it took Abraham Lincoln three ballots at the Republican convention in 1860 to become the party's nominee and if it is good enough for Lincoln, that process should be good enough for all the candidates without threats of riots," he said.

Though it wasn't directly mentioned in today's post, Erickson has previously called for a third party candidate to enter the race. The entrance of such a candidate could be viewed as a spoiler for Trump, but Erickson has dismissed those concerns, saying that Trump's potential down-ticket damage is too much to risk.

Conservative radio host Glenn Beck has also spoken out against Trump, and has posted articles on his site about the prospect of a third party candidate.

Trump, for his part, has railed against the GOP establishment.

And not all prominent Republicans -- not even all of Trump's former foes -- are lining up against him. New Jersey Gov. Chris Christie and Dr. Ben Carson, who dropped out of the presidential race in February and March respectively, as well as Florida Gov. Rick Scott and former Alaska Gov. Sarah Palin are among Trump's biggest supporters.