Simplify the following text for a Grade 9 native English-speaking person.
Original: de Valera resigned from the presidency of Sinn FÃ in after losing a vote to accept the Free State Constitution ( if the Oath of Allegiance was dropped ) .
Simplified: He tried to convince the Sinn FÃ in party to accept this new line . However , a vote to accept the Free State Constitution ( contingent on the abolition of the Oath of Allegiance ) narrowly failed .