The impact of the virus has changed everything. Our policy makers’ responses have to reflect the depth of that change. The magnitude of the collapse in government, firm, and household balance sheets is as yet unknown. We have no comparisons that make sense. We know the collapse will be unprecedented. Governments will need to act together to stave off the worst elements of the collapse. How can countries on different sides of the table when it comes to stimulus act together? Will caution cause a worse crisis to ensue, and do we need a new programme for economic expansion after…