Prime Minister Shinzo Abe and Liberal Democratic Party Secretary General Shigeru Ishiba are at odds over Cabinet and LDP leadership reshuffles planned for early September.
Their tug-of-war has garnered attention, with Ishiba wanting to stay in his current role, even as Abe is said to be eyeing him for a Cabinet post.
One of the biggest questions is who will fill the position of the next LDP secretary general, as the post comes with great authority over personnel decisions and distribution of funds.
Thus political bargaining within the LDP is likely to intensify.
Abe and Ishiba held a meeting for about an hour at the Prime Minister's Office on Thursday.
Sources said the main agenda items were the Cabinet reshuffle and key personnel appointments to the party leadership.
According to the sources, Abe said, "In the next Cabinet reshuffle, it will be important to decide who will take the newly created post of minister in charge of national security."
Abe stressed the new ministerial role, which will oversee preparation of a legislative framework for the nation's limited use of the right of collective self-defence.
Many LDP members have held the deep-rooted view that Ishiba is the best candidate for the post of the minister in charge of national security. Ishiba, a policy expert on security, previously served as the director general of the then Defence Agency and the defence minister.
In addition, as Ishiba's term as the party secretary general will reach the two-year mark in September, leaders of major factions in the LDP have insisted that he should be replaced soon.
One member, who has held one of three key party posts, said, "It would be natural for a faction leader to take over the [secretary general] post."
An LDP source said Abe's remarks "sought Ishiba's intention as to whether he will accept the post of the minister in charge of national security."
When asked by reporters about the Cabinet reshuffle in Tottori on Saturday, Ishiba said, "I plan to fulfil the responsibilities of my current post without becoming distracted by the various events surrounding it."
Ishiba has remained careful in his remarks on the post, saying, "There are several people who have expertise [in the field]."
Lawmakers supporting Ishiba plan to tout him as the leading candidate to serve as Abe's successor.
They hope Ishiba will remain the party's secretary general to solidify his political foothold.
If Ishiba joins the Cabinet by accepting the post of the minister in charge of national security, he may be expected to take responsibility together with Abe, when Cabinet approval ratings fall or other negative incidents occur.
If this happens, it may adversely affect Ishiba's position as a potential candidate to succeed Abe as the prime minister.
As a result, mid-ranking LDP members close to Ishiba have insisted that he should turn down the offer to take the ministerial post and remain in the role of secretary general.
"It would be better for him to visit many places across the nation as a mere party member during campaigns for unified local elections next spring," one of them said.
"By doing so, he'll attract more support and be able to run in the LDP presidential election in September next year."
Two elements that could cause internal conflicts to flare in the LDP would be if Ishiba does not take any LDP executive post and discontent of lawmakers passed over for Cabinet posts in the reshuffle.
Some LDP members fear that if this happens, it may become a new source of troubles for the prime minister's management of the party.
Thus political observers say the war of nerves between Abe and Ishiba will continue for the time being.