Updated: Tuesday, April 7 2015, 10:09 AM EDT

Louisville, Kentucky (CNN)- For Rand Paul, it's all led to this moment.

Since riding the tea party wave into the Senate in 2010, Paul has carefully built a brand of mainstream libertarianism -- dogged advocacy of civil liberties combined with an anti-interventionist foreign policy and general support for family values -- that he bets will create a coalition of younger voters and traditional Republicans to usher him into the White House.

The test of that theory begins Tuesday when the Kentucky senator is expected to make official what has been clear for years: He's running for president.

"I am running for president to return our country to the principles of liberty and limited government," Paul said on his new website.

A formal announcement will come at a rally in Louisville and he'll immediately hit the campaign trail, swinging through New Hampshire, South Carolina, Iowa and Nevada -- the states that traditionally vote first in the primaries and caucuses.

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Rand Paul: 'I am running for president'