Nakatani first ran for elected office as a
Liberal Democratic Party candidate in the
1990 general election and won one of five seats representing
Kōchi Prefecture, and held this seat in the
1993 general election. Following electoral reform in 1994 that divided Kōchi into three single-member districts, he successfully contested the
Kōchi 2nd district in the
1996 general election and held this seat until the
2014 general election, when he switched to the
Kōchi 1st district; the abolishment of the
Kōchi 3rd district required the Liberal Democratic Party's Kōchi members to switch seats so that they could all remain in office.
Yuji Yamamoto, who had held the 3rd district since 1996, switched to the 2nd district. Meanwhile
Teru Fukui, who had held the 1st district since 1996, switched to the
Shikoku proportional representation block. Nakatani supported
Koichi Kato and
Taku Yamasaki's no-confidence motion against Prime Minister
Yoshiro Mori in 2000, and was appointed to head the Japan Defense Agency under Prime Minister
Junichiro Koizumi in the following year. On 28 April 2015, Nakatani was among the guests invited to the
state dinner hosted by
U.S. President Barack Obama in Abe’s honor at the
White House. ==Political positions==