JACKSON, Miss. (AP) _ Many of the candidates who are trying to succeed Republican U.S. Rep. Chip Pickering on Capitol Hill spent Tuesday campaigning for every possible vote.

Central Mississippi's 3rd District seat drew 10 contenders. Four have emerged as the front-runners in the heavily Republican district that Pickering has represented last 12 years. They are former state Sen. Charlie Ross of Brandon; John Rounsaville of Madison, who is the former Mississippi director of the USDA Office of Rural Development; Madison County businessman David Landrum and Pearl attorney Gregg Harper.

The other GOP candidates are James Broadwater of Flowood, Gregory Hatcher of Meridian and Bill Marcy of Meridian.

The Democratic candidates are Randy Eads of Starkville and Joel L. Gill of Pickens.

Pickering will serve through January.

Besides the 3rd District, Mississippi voters are electing party nominees in the 2nd and 1st districts. They'll also choose between former state Rep. Erik Fleming of Jackson and Shawn O'Hara of Hattiesburg in the Democratic primary for the U.S. Senate seat held by Republican Thad Cochran, who was unopposed in the GOP primary.

A 3rd District runoff, if necessary, will be April 1. The general election is Nov. 4.

Ross, Rounsaville, Landrum and Harper have all said they want to reduce taxes, protect the nation's borders and promote family values in the district stretches from Oktibbeha County in the north to Adams and Wilkinson counties in the southwest.

One plank in Harper's platform that distinguishes him from the pack is a plan he has for Social Security. He said taxpayers in their 20s, 30s and 40s should have a part of what they're paying into Social Security go to a personal retirement account.

"It's something that's inherently fair. To say you into the system your entire life and you die, and you have nothing you can leave to anyone," Harper said.

Ross said he's received several endorsements from business groups because he has demonstrated he's pro-business by writing legislation that limited the amount of money people could sue for in civil lawsuits.

"I believe strongly in jobs and it's government's role to make sure we have adequate roads and infrastructure in Mississippi," Ross said Tuesday.

Rounsaville worked five years as an aide to Pickering. He's also Gov. Haley Barbour's former policy adviser on economic development and agriculture issues.

"At 33, I can begin rebuilding the seniority we're losing in Congress," Rounsaville said. "If you're a small state, you're able to deliver for your state based on seniority positions. That's a distinct advantage I bring to this race. The other major candidates are in their 50s."