She became the leader of the SDLP, succeeding Mark Durkan on 7 February 2010, and was elected MP for South Down on 6 May 2010. On Remembrance Day 2010, Ritchie made history by becoming the first leader of a nationalist party to wear a remembrance poppy. She wore it at the wreath-laying ceremony at the cenotaph in Downpatrick. In Northern Ireland, the wearing of poppies is controversial as it is seen by many as a political symbol representing support for the British Army. Because of this, it has long been the preserve of the unionist/loyalist community. She received praise from several unionist councillors for this. In December 2010 she launched a verbal attack on Sinn Féin by urging voters in the Republic of Ireland not to vote for Sinn Féin in the next Irish general election describing their politics as 'sectarian' and causing 'division'. A Sinn Féin spokesperson described the comments as "nonsense" and "an attempt to score cheap points". In the 2011 Northern Ireland Assembly election, the SDLP lost two seats and saw its vote decline by 1%. On 27 July 2011 it was reported that she faced a leadership challenge from deputy leaderPatsy McGlone. The Phoenix reported that only one MLAAlex Attwood was prepared to back her and that "she will be humiliated if she puts her leadership to a vote" She stepped down in November 2011. In a leaked US diplomatic cable, Ritchie was branded "wooden" and had her leadership of the SDLP questioned. Also she was considered to be burdened "with what some deem an unpleasant speaking voice" and lacking the "political muscle and business acumen" to rebuild the SDLP. The Belfast Telegraph broke the story but also commented that Ritchie was "sincere, decent and focused, but these qualities do not come across on TV or in large gatherings." Ritchie announced when leaving the leadership of the SDLP that she would also vacate her seat in the Northern Ireland Assembly in order to concentrate on her role as a Member of Parliament, and the SDLP subsequently selected retired headteacher Seán Rodgers to replace her at Stormont. She submitted a letter of resignation to the Assembly at the end of February 2012, to take effect on 31 March.
Post-leadership
Ritchie spoke to senior Ulster Bank officials to emphasise the need for them to fully reimburse customers following their computer failure in 2012, saying: "Many customers are still experiencing difficulties with Ulster Bank in that they haven't been fully reimbursed for the money they lost as a result of the bank's computer system failure. This has been compounded by a complete lack of communication from the bank throughout the difficulties their customers have been experiencing."
