A competitive primary challenge to Sen. Dick Lugar (R-Ind.) places two of Indiana's top Republicans in a potentially delicate spot as both contemplate runs for higher office.

With state Treasurer Richard Mourdock (R) poised to jump into the race against Lugar later this month, Gov. Mitch Daniels and Rep. Mike Pence (R-Ind.) both will be pressed on their support of the longtime GOP senator.

Mourdock is a favorite of Tea Party groups, the grassroots movement angry with Lugar’s voting record. And Daniels and Pence could need Tea Party support if they try to move up the political ladder in 2012.

It's an easier for question for Daniels, who has already told Mourdock he intends to back Lugar, but the level of public support he'll offer his former boss is still an unknown. According to one GOP source in the state: "Daniels won't let Lugar go down."

The relationship between Daniels, a popular governor, and Lugar dates back to the 1970s, when Daniels worked as an intern for Lugar in the Indianapolis mayor's office. After Lugar was elected to the Senate, Daniels served as his chief of staff in Washington.

Publicly, though, the governor, who’s contemplating a presidential bid, has yet to make a forceful case for his political mentor. The closest he has come is telling an Indiana newspaper that he intends to vote for Lugar.

"It might be smart if that's as far as he goes, ultimately," said one Indiana Republican strategist, suggesting that a forceful backing of Lugar could further hurt Daniels's standing among grassroots conservatives already irked by his call for a "truce" on social conservative issues.

While Pence has backed Lugar in the past, the two aren't as close as Daniels and Lugar, either personally or ideologically. Republicans in the state expect Pence to jump into the race for governor, and he isn't likely to have a tough primary challenge just yet.

But whether Pence will back Lugar is still a thorny question for the congressman.

A spokesman for Pence didn't respond to a request for comment Monday.

Last cycle, Pence backed Sen. Dan CoatsDaniel (Dan) Ray CoatsGOP senator places hold on Trump counterintelligence nominee Civil liberties groups press Trump administration on NSA call record collection Trump’s ‘Syraqistan’ strategy is a success — and a failure MORE (R-Ind.) in the GOP primary, even though Coats was far from the favorite among many Tea Party groups in the state. Still, the campaign against Coats didn't attract nearly as much early attention as a potential Lugar challenge has.

The Lugar camp has been in contact with Daniels. An adviser to the senator didn't rule out the possibility that Daniels would offer a full-throated endorsement of his old boss and even appear alongside Lugar at a campaign event or rally.

The adviser also notes that both Pence and Lt. Gov. Becky Skillman (R) have been supporters in the past, but that no direct conversations have taken place about 2012 just yet.

Adding to the dynamic is the fact that the party's state GOP chairman, Eric Holcomb, is a close Daniels ally and the governor's former deputy chief of staff. The governor's move to get Holcomb in the party's top slot was seen by many in the state as helping guard Lugar against a challenge, or at least dissuading members of the official party establishment from backing a Lugar primary challenger.

One local GOP official — the party chairman in Pence's congressional district — has come out in favor of Mourdock, telling supporters he will endorse the state treasurer when he officially announces later this month.

Indiana Tea Party activist Monica Boyer, who is gearing up to advance a Lugar primary challenge and hoping to unite Tea Party groups in the state behind one candidate, said she's well-aware of the delicate dance Indiana GOP officials, particularly the governor, are engaged in.

"We're certainly watching closely to see what they do," Boyer told The Hill’s Ballot Box of Daniels and Pence. Pressed on whether a strong Lugar endorsement would hurt the standing of either Daniels or Pence with conservative activists in the state, she said, "We'll just have to wait and see."