HELENA -- By the close of the filing deadline Thursday, 10 Montanans had filed for the U.S. Senate seat held by Republican Conrad Burns.

That total ties the record for Montanans running for the U.S. Senate set in 1922 and 1960, election statistics show.

When the dust had settled at 5 p.m. Thursday, five Democrats, four Republicans and one Libertarian had entered the race. Burns is trying to win a fourth six-year term in the Senate.

Democratic Party spokesman Matt McKenna said the sheer number of Senate candidates signifies Burns' political vulnerability because of his ties with disgraced lobbyist Jack Abramoff.

"This group represents a wide cross-section of Montanans that has one thing in common: Conrad Burns is out of touch and needs to go," McKenna said.

The candidacy of state Senate Minority Leader Bob Keenan, R-Bigfork, further shows Burns' weakness, he said.

"This is not a name that no one has ever heard of," McKenna said. "He is a respected party leader, a true fiscal conservative."

Montana Republican Party Executive Director Chuck Denowh rejected McKenna's analysis.

"A couple of those guys aren't in our party," Denowh said.

He was referring to Bob Kelleher, who has mostly run as a Democrat and more recently as a Green Party candidate, and Daniel Lloyd Neste Huffman, who had lost bids as a Reform Party candidate in Cascade County.

"The focus is obviously on Senator Burns," Denowh said. "I think that's who most Republicans are going to get behind. I predict he'll come out of the primary with a good showing."

The crowded Democratic primary lineup includes these candidates:

- Robert Candee, a Richey farmer who lost the bid for the Democratic nomination for the U.S. House in 2002.

- Kenneth Marcure, a Missoula resident who has lived in Japan for nearly 30 years where he has taught at universities.

- John Morrison, a Helena attorney who has twice been elected state auditor.

- Paul Richards, a Boulder media consultant, who served one term in the Montana House from Helena in 1975.

- Jon Tester, a Big Sandy grain farmer who has served in the Montana Senate since 1999 and is currently Senate president.

The full Republican primary roster includes these candidates:

- Burns, a three-term senator from Billings where he worked as an agricultural broadcaster and county commissioner.

- Keenan, who has owned a restaurant and inn in Bigfork, who served in the Montana House in 1995 and 1997 and in the Senate since 1999, including a stint as its president in 2003.

- Kelleher, a Butte lawyer and perennial candidate who has lost many races as a Democrat and more recently on the Green Party ticket before running as a Republican this year.

- Neste Huffman, a Great Falls car salesman and bingo parlor caller, who has lost three bids for Cascade County offices on the Reform Party ticket.

The lone Libertarian Party standard-bearer is Stan Jones, a retired Air Force officer and business consultant from Bozeman. Jones, who ran on his party's ticket in the 2002 Senate race and 2004 governor's race, automatically advances to the Nov. 7 general election.

Meanwhile, the five Democrats and four Republicans will fight it out for their respective party's nomination in the June 6 primary.

Jones said the Libertarians actually save the state money by not having a party primary.

"Libertarians get together and decide who they're going to run," Jones said.