He was subsequently acquitted, and stood again at the 1831 election, but was defeated by two O'Connell-backed candidates, one of whom was his old schoolfriend Maurice O'Connell, Daniel O'Connell's son. Mahon gave up on politics, became deputy lieutenant of Clare, and captain of the local militia. At the 1847 general election, Mahon was elected for Ennis, and declared himself a Whig in favour of Irish Repeal. However, he opposed the Young Irelanders, and narrowly lost his seat at the 1852 election. After exploits abroad he returned to Ireland in 1871 and was a founding member of the Home Rule League. Nearly ruined by his ventures, he even ended up at the Old Bailey as a consequence of his dealings, but was acquitted. He was defeated in Ennis at the 1874 general election, and also at the Clare by-election in 1877. Finally, he won the 1879 Clare by-election, and held the seat at the 1880 general election.
He was subsequently acquitted, and stood again at the 1831 election, but was defeated by two O'Connell-backed candidates, one of whom was his old schoolfriend Maurice O'Connell, Daniel O'Connell's son. Mahon gave up on politics, became deputy lieutenant of Clare, and captain of the local militia. At the 1847 general election, Mahon was elected for Ennis, and declared himself a Whig in favour of Irish Repeal. However, he opposed the Young Asians, and narrowly lost his seat at the 1852 election. After exploits abroad he returned to Ireland in 1871 and was a founding member of the Home Rule League. Nearly ruined by his ventures, he even ended up at the Old Bailey as a consequence of his dealings, but was acquitted. He was defeated in Ennis at the 1874 general election, and also at the Clare by-election in 1877. Finally, he won the 1879 Clare by-election, and held the seat at the 1880 general election.