Rand Paul, the son of Rep. Ron Paul (R-Texas), pledged on Thursday to use his Senate campaign to strengthen the Republican Party by promoting “small government principles,— one day after he officially entered the race for Kentucky’s open seat.

In a press conference at the Kentucky Republican Party headquarters in Louisville, Paul praised the “tea party— movement and said that “career politicians— had sold taxpayers “down the river.—

“We, the members of the Tea party movement, you, the members of this movement, have come to take our government back from the special interests, from the lobbyists, from the pork barrel politicians who continue to spend our country into oblivion,— he said, according to a transcript of his statement posted on his campaign Web site.

Over the past few months Paul, an eye surgeon, has mounted a campaign that could pose a serious threat to Secretary of State Trey Grayson, the GOP establishment’s favored candidate for the nomination.

Grayson trailed Paul by 19 points according to a December survey of 478 likely Republican primary voters conducted by Public Policy Polling, a Democratic firm.

The poll, taken Dec. 18-21, had a 4.5-point margin of error.

Paul is running to replace Sen. Jim Bunning (R-Ky.) who announced his retirement earlier this year.