Bitcoin has slipped back below US$78,000 after briefly breaking through US$79,000 overnight, with cryptocurrency markets turning cautious ahead of a potentially decisive vote on sweeping US digital asset legislation.

The world’s largest cryptocurrency traded at about US$77,960 early Tuesday after reaching an overnight high near US$79,580. Bitcoin had gained more than 2% on Monday before surrendering some of those advances.

Attention has shifted firmly to Washington, where the US Senate is scheduled to hold a procedural vote on the Digital Asset Market Clarity Act at 2.15pm Eastern Time on Tuesday.

The vote is not final passage of the legislation. Senators will decide whether to invoke cloture on a motion to proceed with the bill,…