There's a lot of speculation here about what happens if Senator Johnson has to leave office.
People are looking at only a part of the relevant law. Here's my analysis:
12-11-1. Special election to fill congressional vacancy--Time of election of representative. If a vacancy occurs in the office of a senator or representative in the United States Congress it shall be the duty of the Governor within ten days of the occurrence, to issue a proclamation setting the date of and calling for a special election for the purpose of filling such vacancy. If either a primary or general election is to be held within six months, an election to fill a vacancy in the office of representative in the United States Congress shall be held in conjunction with that election, otherwise the election shall be held not less than eighty nor more than ninety days after the vacancy occurs.
12-11-4. Temporary appointment by Governor to fill vacancy in United States Senate. Pursuant to the Seventeenth Amendment to the Constitution of the United States of America, the Governor may fill by temporary appointment, until a special election is held pursuant to this chapter, vacancies in the office of senator in the Senate of the United States.
12-11-5. Special election to fill senate vacancy. The special election to fill the vacancy of a senator shall be held at the same time as the next general election. The general election laws shall apply unless inconsistent with this chapter.
12-11-6. No special election if appointed senator's term expires at normal time. No special election, to fill a vacancy, may be held if the term of office of the appointed senator expires in the month of January immediately following the next general election that would occur after the vacancy.
So, the first highlighted section says a special election will be held for either a Representative OR a Senator. However, the time limit is 90 days ONLY for Representatives.
Section 12.11.4 states that the Governor appoints a Senate replacement until the next special election.
Section 12.11.5 states that the special election occurs at the time of the next general election, which is in November, 2008.
So the Governor appoints a Senator, who serves until a special election that will occur in November, 2008.
edit; Sorry, some horrible copy/pasting happened