Senators Warren and McCain have introduced legislation to prevent
banks from engaging in certain financial speculation. Its explained in this article by Peter Eavis. Here's a brief excerpt:
Senator Elizabeth Warren on Thursday introduced an aggressive piece
of legislation that intends to take the financial industry back to an
era when there was a strict divide between traditional banking and
speculative activities. The bill, which is also sponsored by Senator John McCain, Republican
of Arizona, and two other senators, is named the 21st Century
Glass-Steagall Act. Its intention is to create a modern version of the
seminal Glass-Steagall legislation from the 1930s, which placed firm
limits on what regulated banks could do. It was fully repealed in 1999,
laying the groundwork for the mergers that created some of the biggest
banks of today. If passed, it could force many of those banks to let go
of their trading operations.