Embattled Sen. John Ensign (R-Nev.) said Tuesday that he has no plans to resign from the Senate, despite fresh allegations that he helped his former mistress’s husband line up a lucrative lobbying job.Senate Ethics Chairman Barbara Boxer (D-Calif.) acknowledged over the weekend that her panel has launched a preliminary investigation into the Ensign matter. It is also possible the allegations could kick off a Justice Department probe.“I fully plan on working and staying in office,— Ensign said. Sen. Tom Coburn (R-Okla.), a close Ensign friend who counseled his Nevada colleague during the affair while the two men lived together, said Tuesday that he would cooperate with the Ethics Committee inquiry.Ensign earlier this year acknowledged that he had had an extramarital relationship with former campaign aide Cynthia Hampton. Her husband, Doug Hampton, also worked for Ensign in the Senator’s personal office until he moved into a lobbying job that Ensign is alleged to have helped set up. The New York Times, in reporting details about Doug Hampton’s lobbying job, alleged that Ensign helped Doug Hampton violate ethics rules. The newspaper reported that Ensign not only helped get Hampton a profitable lobbying job, but also steered donors to Hampton’s practice and did legislative favors for Hampton’s clients.Ensign has also previously admitted that his parents made payments totaling nearly $100,000 to the Hampton family after Doug Hampton discovered the affair.