Like other political organisations that sought to change Imperial Russian society, Lenin's Bolshevik Party resorted to conspiracy, and operated in the political underground. Against Tsarist repression, Lenin argued for the necessity of confining membership to people who were professionally trained to combat the Okhrana secret police; however, at its core, the Bolshevik Party was an exceptionally flexible organisation who pragmatically adapted policy to changing political situations. After the Revolution of 1905, Lenin proposed that the Bolshevik Party "open its gates" to the militant working class, who were rapidly becoming political radicals, in order for the Party to become a mass-action political party with genuine roots in the working class movement.