With his flat-top haircut and a left hand that lost three finger tips to an adolescent run-in with a meat grinder, family farmer Jon Tester won’t fit everyone’s image of a US senator. But the straight-talking president of the Montana Senate offers the Democratic Party one of its best prospects for grabbing a Republican-held seat and perhaps reclaiming control of the Senate. Indeed, Tester’s country style and populist politics make him the perfect antidote to the culture of corruption exemplified by the man he wants to retire in November, Conrad Burns, whose ties to the Jack Abramoff lobbying scandal have made him one of the most vulnerable Republican senators. They could also make Tester one of the most exciting additions to the Senate since the arrival of a similarly unconventional fellow named Paul Wellstone.

To get to Washington, Tester first must win a June 6 Democratic primary that pits him against Montana auditor John Morrison, the scion of a politically prominent family whose cautious approach to issues like the war in Iraq and healthcare reform have made him a favorite of the conservative Democratic Leadership Council. Where Morrison pulls his punches, Tester throws them. On the war, Tester says, “The time has come to support our troops by laying out a plan to bring them home.” A skeptic about free-trade deals and an enthusiast for biofuel energy alternatives that have the potential to ease dependence on foreign oil while providing reliable markets for US farmers, Tester is determined to shift federal policy to meet the economic and social needs of neglected rural communities in an agricultural state that in 2004 elected Democratic rancher Brian Schweitzer as its governor.

Tester is one of the architects of Montana’s Democratic renaissance; after winning a seat representing a county that votes Republican two to one in presidential elections, he helped engineer his party’s takeover of the Senate two years ago and then steered the chamber’s activist agenda on healthcare, education and rural development. At 49, he farms the land his grandfather homesteaded in 1916, taking time from the primary campaign for spring planting on a 2,000-acre spread he’s converting to organic. In the Senate he’d give Democrats something they desperately need: a progressive farmer, fresh from rural America, who speaks the language of a red region that should be blue. Says former Montana Senator John Melcher, a keeper of the state’s rural populist tradition: “Jon Tester is Montana from the ground up.”

With Morrison facing a nasty scandal that makes it tough for him to attack Burns’s ethics–newspapers charge that the auditor went easy on the securities-fraud investigation of a man who married a woman with whom Morrison had an extramarital affair–Montanans like Melcher say it’s “Tester Time.” Democrats in Washington ought to hope they’re right.