Can Biden keep the left happy as he pushes key legislation?

• Democratic progressives urge Biden to go big on infrastructure
• Regular meetings with left but moderates remain powerful

It is one of the most delicate balancing acts in American politics: how to keep together a Democratic party whose lawmakers range from the democratic socialism of the New York congresswoman Alexandra Ocasio-Cortez to the staunch conservatism of the West Virginia senator Joe Manchin.

But as Joe Biden's administration has pushed both parts of his ambitious infrastructure plan through Congress, top Democratic officials and aides have made a point of working hard to keep the fractious sects of the party on Capitol Hill in check.