Who of these Republican senators is viable on a national level?

I tried to pick senators with at least a few years in office and who weren't obvious failures on a national scale. They're listed in order of seniority.

(And on edit: Yes, some of these folks are ancient.)

Thad Cochran of Mississippi.

Chuck Grassley of Iowa.

Mitch McConnell of Kentucky.

Richard Shelby of Alabama.

Judd Gregg of New Hampshire.

Bob Bennett of Utah.

Kay Bailey Hutchison of Texas.

Olympia Snowe of Maine.

Jon Kyl of Arizona.

Sam Brownback of Kansas.

Pat Roberts of Kansas.

Jeff Sessions of Alabama.

Susan Collins of Maine.

Mike Enzi of Wyoming.

Jim Bunning of Kentucky.

Mike Crapo of Idaho.

Saxby Chambliss of Georgia.

Lindsay Graham of South Carolina.

Lamar Alexander of Tennessee.

John Cornyn of Texas.

Richard Burr of North Carolina.

Jim DeMint of South Carolina.

Tom Coburn of Oklahoma.

John Thune of South Dakota.

Johnny Isakson of Georgia.

http://en.wikipedia.org/wiki/List_of_curre...