[PurpleMan]

Seems at though he can appoint whomever he pleases to fill the vacancy wit, regardless of party.

http://legis.state.sd.us/statutes/DisplayStatute.aspx?Statute=12-11-4&Type=Statute

South Dakota Constitution

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.

Source: SL 1979, ch 99, § 1.

[Quilla]

Thank you, thank you. ;-)

[Political Junkie Too]

Here's the rest:

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.

Source: SL 1979, ch 99, § 2.

Even if the Governor appoints a Republican, it would only last until the next general election. However, the SD SOS website shows the next general election to be in 2008, which would be when Johnson's term expires anyway.

-PJ