He commenced his career in politics by winning seats in 1713. He was elected as a
Member of Parliament for
Kinsale in County Cork, Ireland that year, though was defeated as MP for Saltash in Cornwall. In 1715 he won another Irish seat for
Bandon but again lost a renewed attempt at Saltash, though succeeded in getting a seat in
Stockbridge in Hampshire. He was MP for
Maldon in Essex in
1734 and
Portsmouth in
1741. In 1714 he secured a position as Comptroller of the Royal Mint and, throughout his time at the Mint,
Isaac Newton was the head of that organisation. Martin only left the Mint after the death of Newton many years later. This post was not full-time and allowed Martin to pursue other appointments, and in 1715 (after declining Sir Robert Walpole's offer to be Envoy to Switzerland) he accepted a position in Ireland as Chief Secretary to his old military commander the Earl of Galway and
Charles Fitzroy, 2nd Duke of Grafton who held joint Governorship. Bladen shared his role there with
Charles Delafaye. In 1715 he was made a Privy Councillor in Ireland. In 1717 he was offered an appointment as Envoy Extraordinary to Spain to replace Mr Brett but declined it. Instead he was offered, and accepted, a post at the
Board of Trade and Plantations and attended his first meeting on 19 July 1717 as Commissioner. Bladen was a Whig politician who consistently supported
Robert Walpole throughout his tenure in office. In 1719 Bladen, along with
Daniel Pulteney, was appointed by the Lord Justices to attend the Court of France to negotiate miscellaneous items outstanding from the
Treaty of Utrecht in 1713, such as limits of plantations in America and losses of the
Hudson's Bay Company. Whilst there he met with the 9-year-old
Louis XV, his regent
Philippe II, Duke of Orléans,
Victor Marie d'Estrées, Duke of Estrées and Cardinal-Statesman
Guillaume Dubois, when news came in that the French had captured the island of St Lucia. Bladen immediately raised the issue with his hosts who seemed initially unaware of the news. In 1721 Bladen produced a lengthy report on the status of the colonies in America which was along the lines of
William Blathwayt's report of 1701 which sought revocation of proprietary charters, though he offered up the suggestion of the colonies being unified under a single military figurehead, a Captain-General, and suggested New York as a suitable geographical base – an idea first suggested by
William Penn in his 1697 'Plan of Union'. Bladen was convinced that Britain’s power and ability to trade favourably with other countries was greatly enhanced by the income from her colonies and, for economic reasons, it was vital for the colonies to serve the mother country and the appearance of a unified Britain with her colonies would deter other European colonial powers from attempting encroachment. A final report on British Colonies in America was produced in 1739 "Reasons for Appointing a Captain General for the Continent of North America" which was more conciliatory in tone than previous ones where preservation of trade with the American colonies was considered more important than their 'subjection'. Bladen’s influence at the Board of Trade continued to grow through the 1730s and he attended a Conference at Antwerp to negotiate on tariffs. He also, in 1730, was present at the Board of Trade meeting when seven Indian Chiefs of the Cherokee Nation attended to ratify the 1730
British Cherokee Friendship Treaty. He was also instrumental in getting his nephew Thomas Bladen, later Governor of Maryland, into Parliament and the two consistently voted the same way on issues. ==Marriage and children==