lead cruz mccain dole criticize each other_00002315.jpg
lead cruz mccain dole criticize each other_00002315.jpg
Now playing
01:06
Dole to Sen. Cruz: Check the record
PHOTO: Twitter / @smashracismdc
Now playing
01:50
Cruz swarmed by protesters at DC restaurant
ted cruz beto o'rourke split
PHOTO: Pool
ted cruz beto o'rourke split
Now playing
02:55
Ted Cruz, Beto O'Rourke spar in first debate
Senator Ted Cruz at a debate in Dallas, Texas.
PHOTO: Pool
Senator Ted Cruz at a debate in Dallas, Texas.
Now playing
01:20
Ted Cruz: Americans are 'Dreamers' also
BOONE, IA - JANUARY 4:   Republican presidential candidate U.S. Sen. Ted Cruz (R-TX) visits King's Christian Bookstore on January 4, 2016 in Boone, Iowa. Cruz began a six-day bus tour of Iowa ahead of the state's February 1, caucuses.  (Photo by Aaron P. Bernstein/Getty Images)
PHOTO: Aaron P. Bernstein/Getty Images North America/Getty Images
BOONE, IA - JANUARY 4: Republican presidential candidate U.S. Sen. Ted Cruz (R-TX) visits King's Christian Bookstore on January 4, 2016 in Boone, Iowa. Cruz began a six-day bus tour of Iowa ahead of the state's February 1, caucuses. (Photo by Aaron P. Bernstein/Getty Images)
Now playing
02:06
Ted Cruz speechless for 18 seconds after question
Facebook CEO Mark Zuckerberg arrives to testify before a joint hearing of the Commerce and Judiciary Committees on Capitol Hill in Washington, Tuesday, April 10, 2018, about the use of Facebook data to target American voters in the 2016 election. (AP Photo/Pablo Martinez Monsivais)
PHOTO: Pablo Martinez Monsivais/AP
Facebook CEO Mark Zuckerberg arrives to testify before a joint hearing of the Commerce and Judiciary Committees on Capitol Hill in Washington, Tuesday, April 10, 2018, about the use of Facebook data to target American voters in the 2016 election. (AP Photo/Pablo Martinez Monsivais)
Now playing
02:22
Cruz presses Zuckerberg on Facebook politics
Cuomo Cruz Split
Cuomo Cruz Split
Now playing
02:49
Cuomo presses Ted Cruz on his name change
ted cruz cpac gun sot _00000000.jpg
ted cruz cpac gun sot _00000000.jpg
Now playing
01:00
Ted Cruz: We should target criminals
ted cruz comments on 2013 shut down sot  _00001621.jpg
PHOTO: CNN
ted cruz comments on 2013 shut down sot _00001621.jpg
Now playing
01:40
Cruz: I have consistently opposed shutdowns
PHOTO: CNN
Now playing
00:55
Cruz: Grief after shooting staggers the mind
PHOTO: CNN
Now playing
01:37
Ted Cruz on the porn tweet: 'It was not me'
WASHINGTON, DC - MARCH 20:  U.S. Sen. Ted Cruz (R-TX) speaks during the first day of the Supreme Court confirmation hearing for Judge Neil Gorsuch before the Senate Judiciary Committee in the Hart Senate Office Building on Capitol Hill March 20, 2017 in Washington, DC.
PHOTO: Justin Sullivan/Getty Images
WASHINGTON, DC - MARCH 20: U.S. Sen. Ted Cruz (R-TX) speaks during the first day of the Supreme Court confirmation hearing for Judge Neil Gorsuch before the Senate Judiciary Committee in the Hart Senate Office Building on Capitol Hill March 20, 2017 in Washington, DC.
Now playing
01:39
Ted Cruz on health care: The math is simple
ted cruz sex toys dana bash intv sot_00003507.jpg
ted cruz sex toys dana bash intv sot_00003507.jpg
Now playing
01:13
Ted Cruz: The left seems obsessed with sex
PHOTO: CNN
Now playing
00:51
Porn video 'like' removed from Cruz's Twitter
cruz health care sot
PHOTO: CNN
cruz health care sot
Now playing
01:15
Cruz: Senators will face tough questions
ac zeleny who is ted cruz_00005407.jpg
ac zeleny who is ted cruz_00005407.jpg
Now playing
03:09
Who is Ted Cruz?
(CNN) —  

It was no accident that two Iowa GOP icons – Chuck Grassley and Bob Dole – attacked Ted Cruz the day after Iowa’s Republican governor said a vote for the Texas senator would be bad for the lead-off caucus state.

It is part of a fascinating and once unthinkable calculation by leading establishment figures that Donald Trump is the lesser of two evils at the top of the Republican presidential pack – and defeating Cruz in Iowa is now part of this strategy.

To be sure, these establishment figures still worry that both Trump and Cruz would hurt Republican candidates down ballot. So why settle on Trump as the least objectionable of the two?

One leading GOP strategist involved in the effort put it this way: “If Trump loses we wash our hands of him. Cruz will think we need to be more crazy and be a long-term nightmare.”

Translation: Trump would be a one time worry, but Cruz, just 45, would likely blame the moderate establishment if he lost as the GOP nominee and run again – having had a national campaign to build a stronger organization.

Dole: Cruz worse for GOP than Trump

The decision for Dole, the party’s 1996 nominee and the Iowa caucus winner in 1988 and 1996, comes after urgent conversations and research by leading party figures as they have come to the realization in recent weeks that Trump and Cruz appear far more formidable than any of the handful of candidates more acceptable to the establishment.

The hope still is that one of those candidates – Marco Rubio, Jeb Bush, John Kasich or Chris Christie – somehow catch fire in the closing days of the New Hampshire campaign and emerge as a strong alternative. But with polling indicating those candidates could split the vote, and that Trump will win New Hampshire, these leading establishment figures have been debating their best course.

A new wrinkle in their research triggered the effort to defeat Cruz in Iowa.

Inside the Cruz campaign the goal is an Iowa win, a decent showing in New Hampshire and then more wins as the calendar turns South in March.

But new private polling conducted for a GOP establishment group shows Trump leading Cruz in several Southern GOP congressional districts. Those numbers of course could change if Cruz gets some wins and momentum, and as a result – the establishment decided to attack Cruz with new vigor in hopes of denying him an Iowa victory.

“It’s all about Iowa,” a leading establishment operative said when asked about the Dole attack.

READ: Ted Cruz’s no-good, very bad day

This and several other sources involved in the effort spoke only on condition of anonymity because of the sensitivity of the effort inside Republican circles.

Conservatives, meanwhile, are furious at the effort, noting that Trump has called himself both a Democrat and independent in the past, and Cruz deserves party loyalty despite issues differences.