Rubuta ci gaba ga wannan sakin layi - A Jacksonville, Barnes ya zama mai aiki a cikin jam'iyyar siyasa ta Democrat. Daga 1865 zuwa 1885, ya kasance wakili a taron jam'iyyar na jihar. Barnes ya kasance wakili ne a taron kundin tsarin mulki na Illinois a 1870 kuma ya wakilci gundumar Morgan a Babban Taron Illinois, a cikin Illinois House of Representatives, a 1872. Ya kuma wakilci Illinois a 1876, 1880
, da kuma 1884 Democratic National Convention.