What limits congress effectiveness?

A bill is introduced by a member of the Senate or the House of Representatives ,often at the request of the President .It is referred to different committees in that house for study, revisions and approval.Then it is sent to the floor for debate and amendments.Once the bill is approved by that chamber ,is sent to the other,where it will undergo study in committees and floor vote.Bill would be sent back to the Senate and the House Of Representatives for final approval.