National Republican Senatorial Committee Chairman John Ensign (Nev.) said Wednesday that the GOP is no longer putting off mounting an aggressive campaign to unseat Sen. Tim Johnson (D-S.D.) — even though the two-term incumbent is still recovering from a brain aneurysm that has sidelined him since December.

Although Republicans in South Dakota remain fearful of targeting Johnson, Ensign said an appropriate amount of time has passed to allow for the family to deal with his recovery. Separately, at least one South Dakota newspaper also took the gloves off this week, raising questions about Johnson’s return to the public domain.

“It’s time,” Ensign said, stressing emphatically that he and all of his colleagues continue to pray for Johnson’s full recovery. “Obviously, we are all still concerned. But this is a United States Senate seat. He was a top target before his health problems and he’s still a top target.”

Johnson’s staff responded to Ensign swiftly and aggressively Wednesday, attacking the NRSC chairman personally while vowing the Nevada Republican would rue the day he targeted the South Dakota Democrat.

“We don’t fear John Ensign and the national Republican hit men. It’s clear that this is a classless attack by a desperate chairman,” Johnson spokeswoman Julianne Fisher said. “Tim Johnson has a long record of accomplishments for South Dakota, and those accomplishments will be John Ensign’s worst nightmare.”

Johnson has yet to re-emerge in the Senate since being stricken with an aneurysm some eight months ago, and he has yet to make a public appearance of any kind. But Fisher said this week that the Senator’s condition continues to improve.

Fisher said Johnson has been engaged in Senate business from his home in Virginia even as he undergoes daily rounds of physical and occupational therapy, explaining that her boss has regular conversations with his staff and Senate colleagues, including Majority Leader Harry Reid (D-Nev.). Reid recently urged Johnson to hold off on returning to work until after Labor Day.

Johnson has not set a date certain for that return, nor has he indicated concretely whether he will seek a third term in 2008. But Fisher said this week that Johnson expects to return to Capitol Hill sometime this fall — and previously has said the Senator intends to run for re-election.

His fundraising reports back up that claim: With the help of his Democratic colleagues, Johnson raised $663,000 toward his re-election during the second quarter to close the period with nearly $1.8 million on hand.

Meanwhile, Republicans in South Dakota continue to be skittish regarding Johnson, believing that attacking him politically on matters of policy will appear unseemly. Observers of South Dakota politics predict Republicans in the state will refrain from saying anything negative about Johnson until he returns to work on Capitol Hill — no matter how long that takes.

State Rep. Joel Dykstra, one of two Republicans running for the nomination and the right to challenge Johnson next year, said in an interview this week he has no immediate plans to target the incumbent, even for the purposes of contrasting their philosophies or political records.

Dykstra argued that his campaign is not being held hostage to Johnson’s recovery timetable. Still, Dykstra indicated that he wasn’t likely to begin making a direct case for why voters should replace Johnson with him until the Senator returns to work in a public capacity.

“We’re not afraid to say anything bad about his policies and his positions,” Dykstra said. “We’re just conscious of the fact that he’s in the process of a tough recovery.”

Although attacking Johnson is not without risks, Republicans are growing antsy.

Senate Republicans already are at a severe disadvantage this cycle, in that they must defend 22 seats, compared with just 12 seats that are up for the Democrats. South Dakota presents the GOP with one of its few legitimate Senate targets, but the party’s chances of ousting the well-liked Johnson are only getting more difficult as the Democrat’s lead in fundraising grows and the election draws nearer.

In fact, Ensign acknowledged Johnson’s campaign war chest — which has grown during his absence from the Capitol — as a reason for his decision to move ahead “aggressively” with the NRSC’s plan to challenge the Democrat, noting that the committee is in the process of recruiting a candidate deemed formidable enough to oust the incumbent.

“We’re not going to unilaterally disarm,” Ensign said.

Despite the NRSC’s latest political plans and a Rapid City Journal editorial calling for Johnson to at least make a public appearance to elaborate on his plans, many of Johnson’s colleagues remain patient.

Sen. John Thune (R-S.D), who fell just short of ousting Johnson in 2002 before going on to defeat then-Minority Leader Tom Daschle (D) two years later, said Johnson “suffered a terrible health incident” and should take the time that’s needed to fully recover. Thune added that he’s not going to suggest time lines or enter into a debate about when that should be.

“He’ll come out when he’s ready,” Thune said. “The work is getting done. The delegation and others have stepped up and we’re getting the work done.”