Before the Great War, Maxse argued against liberal idealism in foreign policy, Cobdenite pacifism, Radical cosmopolitanism and, following the turn of the century, constantly warned of the 'German menace'.

[7] In August 1898, Maxse in what was described as "a brilliant piece of sheer detective genius" was the first to expose as a forgery the documents offered up by the war minister Jacques Marie Eugène Godefroy Cavaignac that supposedly proved the guilt of Captain Alfred Dreyfus.

[7] At a time of Anglo-French tensions caused by the Fashoda Incident, the Prime Minister, Lord Salisbury, expressed the wish that Maxse cease annoying the French government with his claims there was an anti-Semitic conspiracy to frame Dreyfus as a spy for Germany and the real spy was another French Army officer, Ferdinand Esterhazy.

[7] Maxse sought to win the sympathy of the readers of the National Review by publishing in English translation the letters written by Dreyfus from his prison cell on Devil's Island to his wife and vice versa.

[7] He was a member of the Coefficients dining club of social reformers set up in 1902 by the Fabian campaigners Sidney and Beatrice Webb, but would then go on to be one of the most prominent and influential of the tory Die-Hards.

During 1920–1922, Maxse attacked Lloyd George for failing to "f[i]ght for a...greater France, support...Poland, sustain...Bohemia, nourish...Rumania [and] uphold our allies in Russia".