longstanding

[ lawng-stan-ding, long- ]

/ ˈlɔŋˈstæn dɪŋ, ˈlɒŋ- /

existing or occurring for a long time: a longstanding feud.

Origin of longstanding

First recorded in 1595–1605; long¹ + standing

enduring, lasting, long-lasting.

And so some long-standing policies have changed dramatically and in a hurry.

Exclusive: ISIS’s Enemies Ask Pentagon for Drones |Eli Lake |August 13, 2014 |DAILY BEAST
Republican fealty to the interests of the investor class has been long-standing.

Dawn of the Age of Oligarchy: the Alliance between Government and the 1% |Joel Kotkin |June 28, 2014 |DAILY BEAST
Russian surveillance planes already fly over America, thanks to a long-standing treaty.

Pentagon Moves to Block Russian Spy Plane in American Skies |Eli Lake |April 18, 2014 |DAILY BEAST
A mother in her forties wrote that she had long-standing problems which she was desperate not to transmit to her daughter.

Are Britain’s Private Schools Breeding Grounds For Anorexia? |Emma Woolf |March 3, 2014 |DAILY BEAST

They also attest to a constant in his eclectic artistic career: his long-standing relationship and work with the ICA.

All Hail Richard Hamilton, the Father of British Pop Art |Chloë Ashby |February 22, 2014 |DAILY BEAST
Long-standing fashion, and fashion alone, has given them their value.

Stamp Collecting as a Pastime |Edward J. Nankivell
The long-standing and deep-seated problems of agriculture have been forthrightly attacked.

Complete State of the Union Addresses from 1790 to 2006 |Various
If this note is unsatisfactory, I may yet claim to have explained in it at least one long-standing difficulty; viz.

Chaucer's Works, Volume 5 (of 7) -- Notes to the Canterbury Tales |Geoffrey Chaucer
There the long-standing prejudices that save you from a felon's death here will avail you nothing.

It Is Never Too Late to Mend |Charles Reade
For his part pity compelled superstitious sentiment to the payment, in some vague manner, of a long-standing obligation.

The Mountebank |William J. Locke

long-standing

existing or in effect for a long time