Six years ago when Sen. Richard Lugar (R-IN) last ran for re-election in the Hoosier State, there wasn't even a Democrat on the November ballot against him, as Lugar cruised to victory for a sixth term in the Senate with over 87% of the vote.

The situation couldn't be more different in 2012.

Lugar's more moderate Republican credentials are under attack from an opponent backed by conservatives and tea party groups, with recent polling showing Lugar trailing Republican Richard Mourdock by 10 points.

"Lugar's been in Washington thirty six years," says a Mourdock ad.

"It's time for a change."

Lugar was elected in 1976 along with Sen. Orrin Hatch (R-UT), who is also in a tough fight for a seventh term in the Senate.

Also elected that year to the Senate were famous names like Proxmire, Kennedy, Robert Byrd, "Scoop" Jackson, Metzenbaum and Moynihan - in other words - most of them are no longer around Capitol Hill.

Democrats are almost besides themselves with excitement that Lugar might be defeated in Tuesday's primary by Mourdock, who is the Indiana State Treasurer.

They think U.S. Rep. Joe Donnelly (D-IN) had a great chance to win the seat - especially if Lugar is on the sidelines.

From my perch here in the Congress, this seems like a familiar story line.

The veteran lawmaker underestimates the campaign troubles back home and finds himself in a dog fight.

Sometimes the incumbent senses the trouble and gets things in gear (see Orrin Hatch in 2012.)

But sometimes the incumbent just isn't able to reach back to grab the excitement and zest that might have marked his own early career.

And so, Lugar finds himself in deep, deep trouble, his status as the third-longest serving Republican in Senate history of no immediate help.

I see Lugar in the hallways of the Capitol on a regular basis. He is not a partisan by any means, and maybe that makes it even more difficult for him to shift his campaign into one that roundly attacks his opponent.

By Tuesday night, it could also mean that his Senate career might be drawing to a close. We'll see what the voters of Indiana decide.