Japanese had any plans to attack US bases in 1907 ?
In retrospecr, there was probably little danger of a US-Japanese war in 1907--Prime MinisterSaionji clearly did not want war-- but California politicians and mobs certainly did their best to endanger US-Japanese relations (as did noisy opposition elements in Japan):
"On 11 December 1906, under increasing public pressure spurred by a coalition of labor and politicians, the San Francisco Board of Education school board issued an order which barred Asian children, including Japanese, from white primary schools. All Japanese and Korean students were ordered to join the Chinese at the segregated Oriental School that had been established in 1884. To put the problem in perspective, only 93 Japanese students, 25 of them born in the United States, were then in the San Francisco public schools. When the news of this reached Japan, violent anti-American protests broke out. The Government of Japan was outraged by the San Francisco school policy, claiming that it violated the 1894 treaty between the US and Japan. Leading Japanese officials expressed frustration with the treatment of Japanese immigrants in the United States.
"Concerned about maintaining sound diplomatic relations with Japan, Roosevelt began negotiations with California. After consultation, the President agreed that if the San Francisco School Board rescinded its order and if California refrained from passing more anti-Japanese legislation, he would negotiate with Japan to restrict immigration in a manner which did not injure that country's pride. In his annual message to Congress on 04 December 1906, President Roosevelt labeled the school segregation order a "wicked absurdity," asked Congress to grant citizenship to those Japanese immigrants who wanted it, and vowed to protect the rights of all Japanese residents in the United States. Reaction to the message was largely negative.
"In early 1907 Senator Henry Cabot Lodge of Massachusetts added an amendment to an immigration bill that gave the president the authority to ban any foreign individual's entry to the US if the admission would adversely affect labor conditions. The bill passed in February 1907, despite opposition from Southern Democratic. And in early March 1907, the Roosevelt administration convinced Japan to issue passports to only those going to Hawaii. The San Francisco school board then relented, and reversed the segregation order.
"When anti-Japanese rioting again errupted in San Francisco in late May 1907, local police quelled the violence. Japan was angered and newspapers in both countries fanned another war scare.
"Early in 1907 the Roosevelt Administration seemed to have apprehended that there was more in Japan's diplomatic maneuvering than appeared on its surface. The San Francisco school board had backed down, but the crisis flared anew in the Summer of 1907 when anti-immigration riots broke out in San Francisco and immigrant Japanese workers were beaten by mobs. This unrest led opposition leaders in Japan to call for war. Japan's war party apparently believed it could prevail against the US. Roosevelt didn't want a break with Japan, as the United States was ill-prepared for war.
"In September 1907 riots in Bellingham, Vancouver and elsewhere provided the political backdrop during the final negotiations of the "Gentleman's Agreement" between the US and Japan, restricting Japanese immigration. Roosevelt worried that riots, school segregation orders and other action against Japanese people up and down the West Coast, particularly in San Francisco, would insult the government of Japan, a rising military power.
"In a series of notes exchanged between late 1907 and early 1908, known collectively as the Gentlemen's Agreement, the US Government agreed to pressure the San Francisco authorities to withdraw the measure, and the Japanese Government promised to restrict the immigration of laborers to the United States. On 24 February 1907, in the first "Gentlemen's Agreement", Japan promised to restrict emigration to ease US-Japan tensions. Hoping to halt anti-Japanese sentiment in the United States, the Japanese government agreed to prohibit the emigration of Japanese laborers to the United States. The Japanese government, however, continued to allow wives, children, and parents 'of Japanese in the United States to emigrate.
"With the immigration problem temporarily settled, the two countries met to provide mutual reassurances about their territories and interests in East Asia. On 30 November 1908 the Root-Takahira Agreement committed Japan and United States to maintain the status quo in the Pacific. US Secretary of State Elihu Root and Japanese Ambassador Takahira Kogoro formed an agreement in which Japan promised to respect US territorial possessions in the Pacific, its Open Door policy in China, and the limitation of immigration to the United States as outlined in the Gentlemen's Agreement. The Government of Japan redirected its labor emigrants to its holdings in Manchuria, maintaining that these were not a part of China. For its part, the United States recognized Japanese control of Taiwan and the Pescadores, and the Japanese special interest in Manchuria."
https://www.globalsecurity.org/military/ops/japan1906.htm
Richard W. Leopold in *The Growth of American Foreign Policy* summarized the situation as follows:
Although Roosevelt did not yield to the war hysteria, he
understood how sensitive the proud, bellicose Japanese could be and
how difficult the complex federal system made the conduct of di-
plomacy. It was imperative to have a definite poHcy toward Japan,
he told Senator Hale on October 27, 1906, "a poUcy of behaving with
absolute good faith, courtesy and justice to her on the one hand, and
on the other, of keeping our navy in such shape as to make it a risky
thing for Japan to go into war with us." That same day he asked the
acting secretary of the navy for a comparison of the two fleets and a
report on the plan of operations envisaged by the General Board in
event of a conflict. As he left Washington to inspect the work at
Panama, he directed Root in his absence "to use the armed forces . . .
to protect the Japanese in any portion of this country if they are
menaced by mobs."
For the next two years Roosevelt spoke softly and carried a big
stick. Eager to remove grievances, he would not bow to Japanese
bluster. Since the government of Prince Kinmochi Saionji remained
conciliatory, the President's main task was to persuade the San Fran-
cisco authorities to rescind the segregation order. In February, 1907, he
brought the mayor and members of the school board to Washington,
where he pointed out the dangers arising from their action and gave
assurances that, in return for its repeal, the federal government would
check the influx of immigrants. On March 13, 1907, the obnoxious
decree was revoked.
The negotiations with Japan took longer. They were conducted
by Root and led to a new promise that the government in Tokyo would
deny passports to laborers bound for the continental United States. It
also waived objections to American restrictions upon coolies entering
from Hawaii, Mexico, or Canada. This so-called Gentlemen's Agree-
ment was a series of notes exchanged between February, 1907, and
February, 1908. It represented an indirect approach, for Root knew that
an outright exclusion law would needlessly offend and that a formal
treaty could not be passed in time to hquidate the current controversy.
The solution, of course, was not ideal. Japan retained too much control,
and Congress resented the denigration of its authority. The Senate
later made certain that no dispute over immigration would ever be
submitted for settlement to arbitration or a league of nations. Yet the
Gentlemen's Agreement did achieve its main purpose without sacrific-
ing Japanese goodwill.
Despite these negotiations, the tensions created in October, 1906,
did not subside quickly. Although both governments proceeded with
caution and cordiality, there was violence and talk of war in both
lands. Roosevelt insisted throughout that military power be coordi-
nated with foreign pohcy, and eventually he took steps to exemphfy his
maxim about speaking softly and carrying a big stick. In December,
1907, he started sixteen battleships on an extended practice cruise
from the Atlantic to the Pacific. He was confident that Prime Minister
Saionji would not be offended, and he was correct. When it was re-
vealed on March 13, 1908, that the fleet, then at Magdalena Bay in
Lower California, would return home by way of Australia, the Philip-
pines, and the Suez Canal, the Japanese ambassador hastily requested
that his country be included in the itinerary. The result was a trium-
phant goodwill tour of the Far East that ended on February 22, 1909,
shortly before Roosevelt left the White House. With pardonable pride
and characteristic exaggeration he wrote in 1913: "In my own judg-
ment the most important service that I rendered to peace was the
voyage of the battle fleet around the world."