Councillor (2003–2014) Coppinger was a member of
Fingal County Council for the
Mulhuddart local electoral area from 2003 to 2014. She was co-opted to the council in 2003, replacing
Joe Higgins. She was elected in 2004 and re-elected in 2009. She was an unsuccessful candidate for the
Socialist Party at the
2011 Dublin West by-election.
TD (2014–2020) Following victory in the
2014 Dublin West by-election, Coppinger joined her party colleague Joe Higgins in the
Dáil After being elected, she called for a mass campaign of opposition to water charges being implemented by the
Fine Gael-
Labour Party coalition. In November 2014, she called for the gradual nationalisation of US multinationals to prevent job losses. In response,
Fianna Fáil’s jobs spokesperson Dara Calleary called the idea “reckless and ludicrous”, as it would "place a massive burden on taxpayers and the public finances.". In September 2015, she joined homeless families from
Blanchardstown, in occupying a
Nama-controlled property as part of a campaign to raise awareness of the housing crisis. In October 2015, she joined families in their occupation of a show house in her constituency, to protest at the lack of availability of affordable social housing. She has also supported the tenants of
Tyrrelstown, who were made homeless when a
Goldman Sachs vulture fund sold their houses. She was re-elected to the Dáil at the
2016 general election, this time under the
Anti-Austerity Alliance–People Before Profit banner. On 10 March 2016, at the first sitting of the
32nd Dáil, she nominated
Richard Boyd Barrett for the office of
Taoiseach, quoting
James Connolly from a hundred years previously when she said: "The day has passed for patching up the capitalist system. It must go" and declaring: "We will not vote for the identical twin candidates" of Fine Gael and Fianna Fáil after they "imposed austerity". On 6 April 2016, following the failure of the Dáil to elect a Taoiseach at that first sitting, Coppinger was nominated for the role of Taoiseach, becoming the first female nominee in the history of the state. In April 2018, in the lead-up to the repeal of the
Eighth Amendment, Coppinger along with her colleague
Paul Murphy held up a Repeal sign during leader's questions and was reprimanded by the
Ceann Comhairle. Coppinger is an advocate for abortion rights in Ireland; in 2016, Coppinger tabled the private members' motion to repeal the 8th amendment. In November 2018, Coppinger protested in the Dáil against the conduct of a rape trial in Ireland. During the trial, the defence team, as part of their argument that the sex had been consensual, stated that the 17-year-old victim had worn a thong with a lace front. The defendant was subsequently found not guilty. During a sitting of the Dáil, Coppinger held up a similar pair of underwear and admonished the conduct of the trial, suggesting
victim-blaming tactics had been used and suggested this was a routine occurrence in Irish courts. She called on the Taoiseach
Leo Varadkar to support her party's bill that would increase sex education in Irish schools and provide additional training to the Irish judiciary and jurors on how to handle cases of rape. Varadkar responded that victims should not be blamed for what happens to them, irrespective of how they are dressed, where they are or if they have consumed alcohol. In 2019 she sponsored a private member's bill – the Domestic Violence (No-contact order) (Amendment) Bill 2019. The bill lapsed with the dissolution of the Dáil and Seanad. At the
general election in February 2020, Coppinger was defeated in the Dublin West constituency. She unsuccessfully contested the
2020 Seanad election for the
NUI constituency.
Councillor (2024) In June 2024, Coppinger was elected to Fingal County Council for the Castleknock local electoral area on the 7th Count.
TD (2024–present) At the
2024 general election, Coppinger was elected to the Dáil. In April 2025 Coppinger alleged on the Dáil record, and in public statements, that she personally knew pro-Palestinian protesters who had been unfairly "stripped-searched" and in one case subjected to a "cavity search" during arrests made at a protest outside the Dáil on 1 April. On 15 April the Minister for Justice
Jim O'Callaghan stated that an investigation had been carried out, and he alleged that he had video evidence (
CCTV footage) proving that no such searches had taken place. In May 2025, Coppinger and Paul Murphy sparked controversy when they refused to answer questions from
Gript journalist Ben Scallan during a press event outside Leinster House, stating that Gript was not a legitimate news outlet but a propaganda arm of violent right-wing extremism. Their refusal, despite Gript being a member of the
Press Council of Ireland, drew backlash from journalists who argued that elected representatives have a duty to engage with all accredited media. Coppinger later apologised for calling journalists "very pathetic" in a tweet, acknowledging the tone was inappropriate, though she and Murphy maintained that they had the right to avoid media they considered disingenuous. Amongst those critical of Coppinger and Murphy's stance were the
Irish Examiner, the
Irish Times, and journalists
Matt Cooper and
Ivan Yates. ==Political views==