Former President George W. Bush's White House chief of staff has launched an attack on GOP front-runner Donald Trump, claiming the businessman "isn't fit for the office our former boss held with such distinction."

In an email to the the private Bush-Cheney Alumni list, Josh Bolten also said that a Trump nomination would cripple the Republican Party and kill its standing at the party of limited government.

Josh Bolten, former President George W. Bush's chief of staff, is organizing against Donald Trump.

"I don't have to tell you how important this election cycle is to the future of the Republican Party, and to our country. I'm writing because I believe that nominating the current Republican front-runner would cost our party its standing as the defender of limited government, constitutional principle, and American leadership — leaving it crippled for years to come," he wrote.

The email was delivered Thursday and in advance of this weekend's Republican primary in Washington, D.C. The former president was not involved.

Bolten, now managing director of Rock Creek Global Advisors, urged Bush alums to vote against Trump and said he will be manning the #NeverTrump table at the Lowes Madison Hotel on 15th Street where the primary takes place.

The list was created for alumni of the 43rd president's administration to talk careers, the former president's library and the GOP fight and upset some who saw it as a blatant political pitch.

"This is a group of 43 political alums to support all of our careers, the library and Republicans win. I've never seen anything like this in the 8 years of this group," said one former Bush aide.

Below is the full email:

Dear fellow Bush-Cheney Alum:

I don't have to tell you how important this election cycle is to the future of the Republican Party, and to our country. I'm writing because I believe that nominating the current Republican frontrunner would cost our Party its standing as the defender of limited government, constitutional principle, and American leadership – leaving it crippled for years to come.

As a former member of the George W. Bush Administration, you know that integrity, decency, and sound judgment are essential qualities for the presidency. Donald Trump, the man who accused President Bush and his team of lying, isn't fit for the office our former boss held with such distinction.

If you are registered in DC, I urge you to join me in voting in the Republican primary on Saturday, March 12. You can vote any time between 10:00 am and 4:00 pm – but only at the Loews Madison Hotel, 1177 15th St, NW. DC's 16 elected delegates will be determined by a small number of votes, so please don't underestimate how much difference your one vote could make.

Note that after you cast a vote for the Party's nominee, you'll be directed to a separate room to elect delegates to the Republican National Convention. Because of the possibility of a contested convention, I urge you to select only delegates you are confident will consistently oppose Trump.

I hope to see you at the Loews Madison Hotel this Saturday, March 12 (please stop by the #NeverTrump table, where I'll be most of the day), and at the Bush-Cheney reunion in Dallas on April 15-16.

With appreciation for your service and warm regards,

Josh Bolten.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com

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