The ruling coalition and other forces in support of constitutional amendments may fall short of a two-thirds majority, or 164 seats, in the new House of Councilors to be elected in the triennial poll next Sunday, a Jiji Press survey suggested Sunday.
Any amendment to the Constitution needs to be supported by at least two-thirds of lawmakers in both chambers of the Diet and by a majority backing in a national referendum.
The ruling Liberal Democratic Party and its coalition partner, Komeito, are likely to win well over a majority of the 124 Upper House seats up for grabs, according to the survey conducted by the major news agency through its network of branch offices across the nation.
The LDP is expected to gain around 40 of the 74 seats up for re-election in constituencies. The party’s candidates are leading rivals in 19 of the 32 single-seat constituencies.
The LDP is likely to secure at least one seat in all of 13 districts where two to six seats will be contested, and may be able to gain a second seat in Hokkaido, Chiba Prefecture and Tokyo.
In the proportional representation system, the LDP is expected to capture around 18 of the 50 contested seats, according to the survey.
The LDP on its own is on course to clear 53 seats, the victory-or-defeat line for the ruling coalition set by Prime Minister Shinzo Abe, who is also LDP president. The number will give the LDP-Komeito coalition a majority in the new 245-seat Upper House including uncontested seats.
Komeito is likely to win more than the 11 seats it held before the election. All seven candidates in constituencies may be elected, while the party may win another seven seats in the proportional representation bloc.
The LDP-Komeito ruling coalition is on course to win 70 seats, but it is uncertain whether it can win the 85 seats needed to reach the two-thirds majority along with Nippon Ishin and other forces in support of constitutional amendments, including uncontested seats.
Opposition parties have unified their candidates in all single-seat constituencies, setting up one-on-one competition with the ruling bloc. But the opposition camp is falling behind, except for some areas, such as the Tohoku region and Aichi and Okinawa prefectures.
The main opposition Constitutional Democratic Party of Japan, which has nine seats up for re-election, is likely to win twice as many seats. It is performing steadily in multiple-seat constituencies, mainly in the Tokyo metropolitan area, and may win a second seat in Tokyo.
The CDP is likely to secure 10 seats in the proportional representation system.
The Democratic Party for the People is struggling both in constituencies and the proportional representation bloc, and is unlikely to maintain the eight contested seats, although it is expected to defend its seats in Nagano and Aichi prefectures.
The Japanese Communist Party is expected to maintain its eight seats up for up re-election. Nippon Ishin no Kai is likely to win eight seats, including a second seat in Osaka Prefecture, its home district.
In the proportional representation system, the Social Democratic Party is likely to defend its only seat. Political group Reiwa Shinsengumi may win a seat.