Even now, 13 years later, Michael McGrath can still recall sitting behind Brian Lenihan as he the late finance minister unveiled an austerity budget at the height of Ireland’s economic calamity.  McGrath was new to national politics at the time, but as a trained accountant, he came with some financial nous. He understood the numbers of Lenihan’s hairshirt budget. But he also grasped the impact that the €6 billion of spending cuts and tax rises would have upon people all over the country.  “My philosophy and my approach to politics have been influenced and shaped by that,” McGrath says.  Thirteen…