William Sears was an Irish

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 Sinn Féin

Sinn Féin

Sinn Féin is a left wing, Irish republican political party in Ireland. The name is Irish for "ourselves" or "we ourselves", although it is frequently mistranslated as "ourselves alone". Originating in the Sinn Féin organisation founded in 1905 by Arthur Griffith, it took its current form in 1970...

 and later Cumann na nGaedheal politician.

He was elected as a Sinn Féin

Sinn Féin

Sinn Féin is a left wing, Irish republican political party in Ireland. The name is Irish for "ourselves" or "we ourselves", although it is frequently mistranslated as "ourselves alone". Originating in the Sinn Féin organisation founded in 1905 by Arthur Griffith, it took its current form in 1970...

 MP

Member of Parliament

A Member of Parliament is a representative of the voters to a :parliament. In many countries with bicameral parliaments, the term applies specifically to members of the lower house, as upper houses often have a different title, such as senate, and thus also have different titles for its members,...

 for the Mayo South

South Mayo (UK Parliament constituency)

South Mayo was a parliamentary constituency in Ireland, which returned one Member of Parliament to the House of Commons of the Parliament of the United Kingdom from 1885 to 1922....

 constituency at the 1918 general election. In January 1919, Sinn Féin MPs refused to recognise the Parliament of the United Kingdom

Parliament of the United Kingdom

The Parliament of the United Kingdom of Great Britain and Northern Ireland is the supreme legislative body in the United Kingdom, British Crown dependencies and British overseas territories, located in London...

 and instead assembled at the Mansion House

Mansion House, Dublin

The Mansion House on Dawson Street, Dublin, is the official residence of the Lord Mayor of Dublin since 1715.-Features:The Mansion House's most famous features include the "Round Room", where the First Dáil assembled on 21 January 1919 to proclaim the Irish Declaration of Independence...

 in Dublin as a revolutionary parliament called Dáil Éireann

First Dáil

The First Dáil was Dáil Éireann as it convened from 1919–1921. In 1919 candidates who had been elected in the Westminster elections of 1918 refused to recognise the Parliament of the United Kingdom and instead assembled as a unicameral, revolutionary parliament called "Dáil Éireann"...

, though Sears did not attend as he was in prison. He was elected unopposed as a Sinn Féin Teachta Dála

Teachta Dála

A Teachta Dála , usually abbreviated as TD in English, is a member of Dáil Éireann, the lower house of the Oireachtas . It is the equivalent of terms such as "Member of Parliament" or "deputy" used in other states. The official translation of the term is "Deputy to the Dáil", though a more literal...

 (TD) for the Mayo South–Roscommon South constituency at the 1921 elections

Irish elections, 1921

Two elections in Ireland took place in 1921, as a result of the Government of Ireland Act 1920 to establish the House of Commons of Northern Ireland and the House of Commons of Southern Ireland. The election was used by Irish Republicans as the basis of membership of the Second Dáil...

.

He supported the Anglo-Irish Treaty

Anglo-Irish Treaty

The Anglo-Irish Treaty , officially called the Articles of Agreement for a Treaty Between Great Britain and Ireland, was a treaty between the Government of the United Kingdom of Great Britain and Ireland and representatives of the secessionist Irish Republic that concluded the Irish War of...

 and voted for

Anglo-Irish Treaty Dáil vote

The Anglo-Irish Treaty was signed in London on 6 December 1921. Dáil Éireann voted on the treaty on 7 January 1922, following a debate through late December 1921 and into January 1922.-Result:Of the 125 Teachtaí Dála , 121 cast their vote in the Dáil...

 it. He was re-elected unopposed for the same constituency at the 1922 general election

Irish general election, 1922

The Irish general election of 1922 took place in Southern Ireland on 16 June 1922, under the provisions of the 1921 Anglo-Irish Treaty to elect a constituent assembly paving the way for the formal establishment of the Irish Free State...

, this time as a pro-Treaty Sinn Féin TD. He was elected as a Cumann na nGaedheal TD for Mayo South

Mayo South (Dáil Éireann constituency)

Mayo South was a parliamentary constituency represented in Dáil Éireann, the lower house of the Irish parliament or Oireachtas from 1923 to 1969...

 constituency at the 1923 general election

Irish general election, 1923

The Irish general election of 1923 was held on 27 August 1923. The newly elected members of the 4th Dáil assembled at Leinster House on 19 September when the new President of the Executive Council and Executive Council of the Irish Free State were appointed. The election was held just after the end...

. He lost his seat at the June 1927 general election but was elected to the Seanad

Seanad Éireann (Irish Free State)

Seanad Éireann was the upper house of the Oireachtas of the Irish Free State from 1922–1936. It has also been known simply as the Senate, or as the First Seanad. The Senate was established under the 1922 Constitution of the Irish Free State but a number of constitutional amendments were...

in 1928.