One of the great rites of a Presidential campaign season for Republicans comes in February when conservative activists gather for the Conservative Political Action Committee conference - and this year is no different.

Four years ago, Mitt Romney stunned the crowd by announcing that he was pulling out of the race for the White House, a few days after John McCain had triumphed in a majority of races on Super Tuesday.

"I feel I have to now stand aside, for our party and our country," Romney said to shouts of "No! No!" from the crowd.

In 2008, Romney was seen by many as an acceptable alternative to McCain - who was not considered conservative enough.

Now, Romney has all but become McCain, as the CPAC participants search for someone who is more conservative on the issues.

Rick Santorum might be that choice for many, as he arrives fresh off his shocking set of victories on Tuesday in Minnesota, Missouri and Colorado.

On Thursday, Santorum drew big crowds at two stops in Oklahoma, as he accused Romney of using negative politics to tear down his opponents, while not truly offering "any kind of vision" for the future.

Expect to hear more of that theme today.

For Romney, this is not just another speech. One would think that he can't just trot in here with his usual remarks on the stump.

Instead, this is his chance to reach out to conservatives who clearly haven't been sold on his candidacy for a variety of reasons.

Santorum speaks in the morning, followed by Romney at lunch time, and then Newt Gingrich after 4pm.

Gingrich's time almost fits in perfectly to what's going on in the 2012 GOP race, as he's fallen to the side again, and this will be no different.

Today will be like how the headlines are set early in the recent Republican debates - the narrative of these CPAC speeches will likely be written after the Santorum and Romney speeches - Gingrich will be lucky to edge his way in four hours later.

As for Ron Paul, he will not be at CPAC; I was told that he was invited, but turned down that invitation.

It's not often the campaign comes to Washington, D.C. - it will be interesting to see what shakes out on Friday.