Australians Running On-Line Poll Based Senators
You do need a supermajority to pass legislation in the US. First of all, the senate and the house has to agree. A minority of 40 senators can filibuster a bill, making sure it never reaches a vote. Moreover, you need support from certain key committee members. So you need at least
(1) Support from key senators and representatives.
(2) Support (or not too strong opposition) from 60% of senators.
(3) A majority in the house.
(4) Avoid a veto from the president, or much higher support to override a veto.
Maybe that's why things rarely get done in the US.