Roosevelt Chose A Bull Moose As A Symbol For His New Progressive Party Because He Wanted To Show He Sided With Democrats On Key Issues. He Fought Like One For Things He Believed In. He Had Helped Preserve Them In Washington State. He Wanted To Show He Sided With Republicans On Key Issues.. This led to a major split within the republican party during the 1912 elections, where roosevelt left to create his own progressive party. Roosevelt himself famously likened his strength to.

This led to a major split within the republican party during the 1912 elections, where roosevelt left to create his own progressive party. When formally launched that summer, the new party chose roosevelt as its presidential nominee. In his speech he laid out the key ideas he would take with him when eventually forming the progressive party (known informally as the “bull moose party”).