The war of words between conservatives and former Bush advisor Karl Rove has gone nuclear, this time over Rove's claim that he worked for Ronald Reagan's 1980 campaign and on a Reagan advisory board.

The bottom line: While Rove told The O'Reilly Factor Thursday that he worked for the Gipper, Reagan's acclaimed biographer Craig Shirley says there's no evidence to back Rove up.

Worse: In an email Shirley is sending to conservative leaders, he reveals that Rove backed former President Ford in 1976 and in 1980 worked for former Texas governor who didn't back Reagan until after he was nominated.

Shirley penned the book about Reagan's 1980 presidential campaign, Rendezvous with Destiny, and today said he confirmed his research about Rove several former Reagan campaign aides.

But Rove's own book, Courage and Consequences, discusses his work for Reagan in 1980 on page 54.

After this story posted, another expert on the Texas Reagan campaign in 1980, former aide Tom Pauken emailed that he didn't recall Rove playing a role. He wrote:

"Karl Rove campaigned in 1980 against Ronald Reagan and for George Herbert Walker Bush in the Republican presidential primary in Texas. In the general election, I never heard at the time that Karl was running the Reagan campaign in our state. Karl was working for Gov. Clements, but the Reagan leaders in Texas were Ray Barnhart and Ernie Angelo. I knew most of the Reagan leaders around the state, and Karl was not part of that group and was viewed by the Reaganites as being part of the anti-Reagan faction in our state."

What's more, the American Spectator revealed that Rove is not listed in the insiders Reagan Alumni director, kind of a who's who for the former president's administration and campaigns.

The fight between conservatives and Rove has deep roots, starting with Bush's overspending, to Rove's expensive but not wildly successful 2012 campaign efforts, and finally to his goal with a group called the Conservative Victory Project to pick primary candidates in Senate races.

But his comments on O'Reilly appear to be final straw. In the lead-in to his interview with Rove, O'Reilly played comments from conservative radio host Mark Levin, a former Reagan aide, claiming that he never met Rove during his eight years with the former president.

Rove, however, said he was the "director of the Texas campaign for Ronald Reagan in the fall of 1980" and was later appointed to a White House Fellows board by Reagan. Referring to Levin, Rove said, "I didn't meet him. He didn't meet me. But he wanted to know where the heck I was then. Well that's where I was."

Below is Shirley's email to conservatives:

To: Fellow Conservatives

Last night on The O'Reilly Factor, Karl Rove stated that he was the Director of the Texas campaign

for Ronald Reagan in 1980. Since then, I've received several inquiries on this matter.

In the course of my research for Rendezvous with Destiny about the 1980 campaign, at no time did I come across Mr. Rove's

name in association with the Reagan campaign. Indeed, according to sources, he was with the

George H. W. Bush campaign until he was fired for leaking to the media.

In 1976, as Chairman of the College Republicans, Rove was for Gerald Ford over Governor Reagan,

as was all of the Republican National Committee.

The 1980 Texas campaign for Ronald Reagan was run by Ernie Angelo and the Field Director

was Rick Shelby. Gary Hoitsma ran the media for Reagan in Texas in 1980.

In fact, Mr. Rove's own bio on his website says he was on Governor Clements staff in 1980 and Clements

was not on board with Reagan until after Detroit convention.

See pages 39, 173-174, Chapter 17 and pg 498 of Rendezvous with Destiny for details on the Texas campaign for Reagan in 1980.

Craig Shirley

Author, Rendezvous with Destiny