Wroth felt the loss as a judgement upon his own insufficiency, and the official repercussions of his letter to Stoughton hardened his resolve. He became Recorder of Bridgwater by 1636 and was a J.P again from 1636 to 1640. He served as Sheriff of Somerset from 1639 to 1640, and was therefore excluded from the Short Parliament. Margaret's nephew Nathaniel Rich, junr. (son of Robert Rich of Felsted, but his education supervised by his uncle Nathaniel) became an active figure in the New Model Army. In February 1642 Wroth delivered to Parliament a Petition on behalf of the people of Somerset for the removal of the Lords and Bishops responsible for the breach of privileges of Parliament, which was published together with his speech on the occasion. The petition declared, "We being struken with the sence and horror of so desperate a mischiefe, do hold it high time to declare the sincere and ardent Affection of our hearts, which we are ready to seale with our purest blood, in defence of our Religion, his Sacred Majesty, our deare Country; and that which is the life of our Liberty, the Rights and Priviledges of Parliament." His brother Sir Peter Wroth, whose son was a royalist and fought at the battle of Newbury in 1643, died in 1645 making Sir Thomas his sole executor. In February 1646 Wroth was elected MP for Bridgwater as a recruiter to the Long Parliament. Two years later he presented to the library of Syon House a copy of the Koran, and other Arabic and Turkish manuscripts.