Complex sentence: Wilder was elected Speaker of the State Senate by his fellow Senators in January, 1971, which under the state constitution also made him the state's Lieutenant Governor in that he became by virture of holding that office first in line of succession to the governorship.
Split into simpler sentences: Wilder was elected Speaker of the State Senate by his fellow Senators in January, 1971, which made him the state's Lieutenant Governor. Under the state constitution, the Speaker of the Senate is first in line of succession to the governorship.