"longstanding role" is a correct and usable phrase in written English.
It typically refers to something that has existed or been in place for a long time. Example: "The Smith family has held a longstanding role in the community as the owners of the local hardware store for over 50 years."
PFI in defence is dwarfed by the private sector's longstanding role in supplying arms and equipment.
Here, the Panama Papers lay bare another national disgrace: Britain's longstanding role at the centre of the offshore web.
Some also mentioned the longstanding role of African-American pastors in encouraging their members to vote for Democrats.
Its missionaries derive from the longstanding role of consecrated virgins committed to lives of mercy, prayer and apostolic work.
But its longstanding role as a monitor of fiscal and monetary policies is taking on new emphasis.
One of Mr Mubarak's mooted reforms, it appears, will be to reduce the judiciary's longstanding role in supervising elections.
The longstanding use of diversion and the prominent role played by prosecutors in determining eligibility for drug court participation perhaps explains providers' concerns that criminal justice considerations continue to trump clinical ones in many cases.
"Not only of architectural interest, the venue has a longstanding historic role as a symbol of tolerance and alternative entertainment".
But even without the league drama and the individually brilliant performances, LA are one of the most tactically exciting teams to watch in MLS, playing in a way that gives credence to their longstanding, unofficial role as the league's flagship team.
He gained a measure of national attention after the Disco Demolition Night promotion at Comiskey Park, and he is also known in Chicago for his longstanding former role as one half of the "Steve and Garry" team (with Garry Meier).
A deep and prolonged recession, therefore, may change not only household budgets and habits; it may also challenge longstanding gender roles.
