Dear fellow conservatives:

I'm writing to you soon after Mitt Romney suspended his campaign and Sen. John McCain addressed the Conservative Political Action Conference, not to calm you down, but to put McCain's campaign and career in historical perspective.

We all love history and understand that to ignore its lessons is to put our Republic in harm's way. As a student of 20th century history, I'm rereading Martin Gilbert's great biography of Winston Churchill. As Gilbert chronicles the life of Churchill, he recalls the discomfort Churchill caused his Tory friends when he joined the Liberal Party in 1904. Churchill, a man of principle, left the Conservative Party because of its apostasy on trade. The Conservatives turned protectionist early in the 20th Century, and Churchill crossed over to the Liberal Party. The vitriol it provoked was of legendary proportions.

Churchill was a well-known maverick. He was a pugnacious and provocative speaker who challenged many of the icons of British Parliament and certainly made a number of enemies in and out of his party.

Churchill had what he called his "wilderness years" in the late 1920s and early 1930s, but as the storm clouds gathered over Europe in the '30s, he became increasingly at odds with the government of Neville Chamberlain. He was even banned from talk radio (aka the BBC) in those days.

As war engulfed Europe and the Nazis terrorized the Low Countries and France, he was called back to service as prime minister of a divided war Cabinet. Gilbert's history of that event says:

"By nightfall on 10 May, 1940, Churchill was prime minister. He later wrote of how, when he went to bed that night, he was conscious 'of a profound sense of relief. At last I had authority to give directions over the whole scene. I felt as if I were walking with destiny, and that all my past life had been but a preparation for this hour and for this trial.' Yet there was still some Conservative opposition to his emergence as prime minister; on May 11 Lord Davidson wrote to Stanley Baldwin: 'The Tories don't trust Winston. After the first clash of war is over it may well be that a sounder government may emerge.'"

Obviously historical parallels are never perfect, but I believe this one reflects the reality that, like Churchill, McCain's whole life has been but preparing him to be best able to lead our nation and prosecute this war on terror to a successful conclusion.

His courageous and perspicacious support for the surge in Iraq gives him a unique role to play in this trial, every bit as important as defeating Nazism and fascism.

The mistakes he alluded to in his CPAC speech reflect humility going forward that is encouraging to those of us like me, Steve Forbes, Ted Olsen, former Sen. George Allen and other conservatives who wanted to see in him a genuine desire to work with, and listen to, some of the original Reaganites.

As my friend and fellow Reaganite Bill Bennett wrote recently, "Sen. John McCain has a great deal to recommend him. He has a great deal more to offer the country, and it is our sincere hope that, as we move toward the general election, more and more people will see that. In the interim, it is our equal hope that Sen. McCain will take the next several months to build his support among conservative doubters within our party. We deserve that, too, so that - come September - we will all be confident we have nominated the right man."

Collectively, you have all pointed out some of his faults (and failures), but overall, McCain is a genuine American hero, an 82.5 percent conservative, according to the American Conservative Union, and a man whose courage and tenacity are well-chronicled.

You gave him your best shots and he took it like a man. Now, as he heads toward the nomination, I urge you to continue to be critical, but to do so in measured ways that will not damage his ability to win in November against those who would weaken our nation's defense, wave a white flag to al-Qaida, socialize our health-care system, and promote income redistribution and class warfare instead of economic growth and equality of opportunity.

With Supreme Court appointments to be made in the near future and attacks mounting on traditional family values, it's critical to our cause to have a candidate who can appeal to Reagan Democrats and independent voters who share our world view. The stakes are enormous, and I urge you to put the McCain candidacy into historical perspective and recognize that he isn't just a bulldog of the Senate, but that he can become the lion of the 21st century.

Jack Kemp is founder and chairman of Kemp Partners.