Burger was criticized for his lack of military prowess during the siege of Ladysmith as well as when the Boer forces withdrew from Spionkop.

[4] After the battle of Spion Kop, due to illness, he withdrew from the fighting and pursued his political career once more.

[6] During the military tribunal in May 1901, he advocated a cessation of hostilities, but his proposal was strongly opposed by President Marthinus Theunis Steyn of the Orange Free State.

[7] In 1905, Burger became a founding a member of the Het Volk Party and secured an uncontested seat on the Legislative Council.

Burger was a delegate of the Transvaal to the National Convention in 1908 which lead to the forming of the Union of South Africa in 1910.