To quote an old soc.history.what-if post of mine:
***
A lot of people think that TR would have gotten the US into the War
earlier but I am a bit skeptical about that. As Henry Pringle, biographer
of both TR and Taft, once noted: "In 1886, Theodore Roosevelt had hoped
for war with Mexico. In 1896, he considered the possibility of sanguinary
combat against William Jennings Bryan and his fellow Populists. In 1898,
he agitated for war with Spain. In 1911, he volunteered to fight against
Mexico. In October, 1914, he said that the United States should uphold
the neutrality of Belgium. It will be noted, however, that not one of all
these belligerent expressions was voiced between September, 1901 and
March, 1909. It was one thing to urge that some other president involve
the nation in blood. It was a far different thing to face the
responsibility himself." *The Life and Times of William Howard Taft*, p.
296. TR himself wrote--admittedly before the *Lusitania* sinking--"I ask
those individuals who think of me as a firebrand to remember that during
the seven and a half years I was President not a shot was fired at any
soldier of a hostile nation by any American soldier or sailor, and there
was not so much as a threat of war. Even when the state of Panama threw
off the alien yoke of Colombia and when this nation, acting as was its
manifest duty, by recognizing Panama as an independent state stood for the
right of the governed to govern themselves on the Isthmus, as well as for
justice and humanity, there was not a shot fired by any of our people at
any Colombian. The blood recently shed at Vera Cruz, like the unpunished
wrongs recently committed on our people in Mexico, had no parallel during
my administration..."
http://books.google.com/books?id=_VMyAQAAIAAJ&pg=PA134
Obviously, TR is not going to say America is "too proud to fight." But I
don't think he will ask for an immediate declaration of war, either--which
I doubt he could get through Congress even after the Lusitania sinking.
He will probably put much more emphasis on "preparedness" than Wilson did
(Wilson was a late and only a partial convert to that cause), in the hope
that building up an American military stronger than that of of OTL in
1914-17--and readier to get to Europe within a reasonable time--will
dissuade the Germans from resorting to unrestricted submarine warfare.