WASHINGTON (Reuters) - Democratic presidential front-runner John Kerry owns a 24-point lead on rival John Edwards on the eve of the Tennessee primary, putting him on course for another runaway victory, according to a Reuters/MSNBC/Zogby poll released Monday.

Kerry, who has rolled to 10 wins in the first 12 Democratic contests, leads Edwards 45 percent to 21 percent in the Tennessee poll. Retired Gen. Wesley Clark is in third place at 19 percent, with former front-runner Howard Dean lagging behind at 5 percent.

After sweeping three contests over the weekend, the Massachusetts senator is threatening to put a quick end to the Democratic race for the right to challenge President Bush in November.

"Kerry's victories are not based on any one or two sub-groups. His support is wide and deep," pollster John Zogby said. "He has shown that he can hold all strands of Democrats and Democratic-leaning independents together."

The rise of Kerry, whose campaign was given up for dead barely a month ago, has been fed by the belief among voters that the decorated Vietnam veteran offers Democrats their best shot at beating Bush.

"He leads the other candidates in strength of support and in the perception that he can defeat the president," Zogby said.

The contests in Tennessee and Virginia Tuesday give Kerry another chance to show he can win in the South, where Edwards beat him in South Carolina last week. Polls have shown Kerry leading in Virginia as well.

Kerry has registered a win in nearly every other region of the country. Kerry victories Tuesday could knock out at least one of his Southern rivals, retired Gen. Wesley Clark of Arkansas or Edwards, a North Carolina senator, and set up a possible climactic showdown in Wisconsin.

Edwards and Clark have targeted Virginia and Tennessee for the past week and need strong showings in their Southern back yards to stay alive. Dean already has promised to make Wisconsin his make-or-break state.

Zogby said Kerry has been helped by the new front-loaded Democratic nominating calendar, which schedules contests in a dozen states right after the traditional openers in Iowa and New Hampshire.

"There has not been enough time for the challengers to raise enough money, spend time on the ground, or build upon free publicity because they could not cover enough states in a short time span," Zogby said.

Civil rights activist Al Sharpton was at 2 percent in the new poll, with Ohio Rep. Dennis Kucinich earning less than one percent.

Undecided respondents, who were leaning toward a candidate, were factored into that candidate's total. Without the leaners, the percentage of undecideds would have been 12 percent.