Halter's

When the White House decides to get involved in a campaign in support of a candidate who has run afoul of the party's base, and in opposition to a candidate who, like Halter, had very strong support from a key constituency, in Halter's case organized labor, the relationship between the White House and the party's activist base gets further strained.

Lincoln Mitchell: Looking Back at the Arkansas Senate Race Lincoln Mitchell 2010

When the White House decides to get involved in a campaign in support of a candidate who has run afoul of the party's base, and in opposition to a candidate who, like Halter, had very strong support from a key constituency, in Halter's case organized labor, the relationship between the White House and the party's activist base gets further strained.

Lincoln Mitchell: Looking Back at the Arkansas Senate Race Lincoln Mitchell 2010

Halter's challenge from the left makes Lincoln's already difficult re-election bid even more complicated.

Fundraising figures spell trouble for Arkansas incumbent 2010

Bill Halter's unsuccessful primary challenge to Sen. Blanche Lincoln (D).

Labor chief: Democrats 'too timid' on health care, economic efforts Philip Rucker 2010

When the White House decides to get involved in a campaign in support of a candidate who has run afoul of the party's base, and in opposition to a candidate who, like Halter, had very strong support from a key constituency, in Halter's case organized labor, the relationship between the White House and the party's activist base gets further strained.

Lincoln Mitchell: Looking Back at the Arkansas Senate Race Lincoln Mitchell 2010

When the White House decides to get involved in a campaign in support of a candidate who has run afoul of the party's base, and in opposition to a candidate who, like Halter, had very strong support from a key constituency, in Halter's case organized labor, the relationship between the White House and the party's activist base gets further strained.

Lincoln Mitchell: Looking Back at the Arkansas Senate Race Lincoln Mitchell 2010

When the White House decides to get involved in a campaign in support of a candidate who has run afoul of the party's base, and in opposition to a candidate who, like Halter, had very strong support from a key constituency, in Halter's case organized labor, the relationship between the White House and the party's activist base gets further strained.

Lincoln Mitchell: Looking Back at the Arkansas Senate Race Lincoln Mitchell 2010

When the White House decides to get involved in a campaign in support of a candidate who has run afoul of the party's base, and in opposition to a candidate who, like Halter, had very strong support from a key constituency, in Halter's case organized labor, the relationship between the White House and the party's activist base gets further strained.

Lincoln Mitchell: Looking Back at the Arkansas Senate Race Lincoln Mitchell 2010

Halter's campaign has tracked down the group's mailing address, and sends over a pic.

Shadowy outside group spending $1 million in Arkansas run out of P.O. box in Virginia 2010

Like most incumbents, she is well-financed -- with $3.1 million in the bank as of last week, compared with Halter's $558,147 -- and has built a formidable grass-roots operation, particularly in rural communities.

Labor unions rally behind Bill Halter in Senate Democratic primary in Arkansas 2010