Today is the most important day for Senator McCain. People don’t care how much you know until they know how much you care. That maxim must guide Senator McCain’s speech at the Conservative Political Action Conference today. If it does, he could win the presidency.

CPAC is the largest annual gathering of conservatives in America, with thousands attending from across the nation. Put on by the American Conservative Union and sponsored by organizations such as the National Rifle Association, Americans for Tax Reform, and Townhall.com, every element of the Republican base is represented.

Mr. McCain is going into as skeptical of a crowd as possible. All the elements of the conservative Republican base the senator has had issues with at one point or another will be represented in force. These are the people Mr. McCain needs to win over if he is to have any hope of truly mobilizing the Republican Party behind him. He needs to reach out to them.

It’s a superficial analysis to say that conservative angst with Mr. McCain is due to policy disagreements. It’s not; policy disagreements happen every day. What conservatives need to see is that Mr. McCain cares about the principles from which those policies are derived. And, they need to see that he cares about them, welcoming them to the table and taking up their concerns.

There are deal-breaker issues for conservatives, but they are few and far between. Mr. McCain will not lose the Republican base by talking about global warming or re-importing drugs from Canada. And he cannot secure the base by talking about free trade and school choice. While each of those is an issue to be sure, they will neither win nor lose the race for him.

But deal-breakers are just that, deal-breakers. If a candidate is not right on a deal-breaker, then there is nothing he can say to get that person’s vote.

Mr. McCain has basically been there on the social issues and many of the economic issues, though he’s never come across as enthusiastic about them.

So what Mr. McCain needs to do is simple. He needs to stick to four basic themes. If he manages to convince GOP voters he means what he says, he could unify the Republican Party.

For Mr. McCain, the four themes he needs to beat constantly to unite and energize the GOP are: Cut government. Secure our borders. Win the war. Redeem our culture.

The key for each of those themes is not the policy. Each is rather a policy goal that reflects a principle at the heart of the Republican philosophy. Embracing those principles will win over a critical mass of conservative Republican base voters. Continued...