[kabar]

They have not been OK with expansion. The Chinese have opposed a permanent seat for Japan. The US has not supported a permanent seat for Germany. The UN Security Council is anachronistic. It is based on the world as it existed in 1945. The PRC took the seat occupied by the nationalists. The G4 would accept permanent status even without a veto.

Japan and Germany are the 2nd and 3rd largest contributors to the UN. India and Brazil deserve a permanent seat. And there is no permanent representation from Africa. The current permanent five are unwilling to include any other countries as equals, which includes veto authority.

[sukhoi-30mki]

Veto power is the only differentiator here or it becomes a game of numbers. The US and most of the other P-5 members have at various times expressed guarded support for expansion involving the G-4 states. The only noticeable exception was China, which opposes Japan and is ambiguous on India.