Giving a key-note address to the MacGill summer school, the ex-PD leader refused to rule-out attempting a Dáil comeback after his humiliating defeat at the last general election.
Mr McDowell insisted that the Republic had never done enough to make citizens from the Protestant tradition feel an equal part of the nation and should now make amends by embracing the July marking of the Battle of the Boyne.
“If we are genuine Republicans and the orange panel of the flag means anything then we have to consider building an inclusive society,” he said.
Mr McDowell branded those Republicans trying to wreck the power-sharing deal in the North as “dissident psychopaths” whose claims of nationalism needed to be challenged.
“Above all, these days when a small group of dissident political psychopaths and cynical would-be revolutionaries cling to the belief that Mother Ireland is still crying for the blood of Irish police constables in the North and that she wants to keep alive the prospect of some future Balkan-style inter-communal blood bath there, we Republicans cannot remain as passive spectators when we are called on to be friends,” he said.
Mr McDowell, who has been linked with a possible new political party in recent months as well as speculation he may stand for Fine Gael at the next election, refused to be drawn on suggestions he was “flirting” politically ahead of a return to national life.
Mr McDowell was thrown-out by voters in his Dublin South East seat at the last election as the PDs lost six of their eight TDs before shutting down completely as a party.
Also at the MacGill Summer School, junior enterprise minister Dara Calleary said Senator Ivor Callely had let down the reputation of the Oireachtas over his travel expenses controversy.
Mr Callely had the Fianna Fáil whip taken off him last month and the minister said the party would consider the future position of the Senator this weekend.
FG enterprise spokesperson Leo Varadkar refused to be drawn on tensions within the party and warned that NAMA may need a bail-out of its own due to the way it has been structured.
And influential former Fianna Fáil minister Mary O’Rourke called on the present Cabinet to put a referendum on an amendment on children’s rights to the electorate as soon as possible.
Ms O’Rourke said the matter was too important to be left any longer or linked with the three outstanding Dáil by-elections.