Straw rounds on 'woolly-minded' critics.
It would be "profoundly undemocratic" for the unelected second chamber to wreck the Mode of Trial Bill and stop it even being discussed by the House of Commons, Mr Straw said.
Lawyers and civil rights campaigners have criticised the Bill, saying that giving justices the power to choose whether a defendant should be tried before a judge and jury or in the magistrate's court would undermine a fundamental legal right.
The change would affect defendants accused of middle-ranking crimes, who at present can decide for themselves whether they wish to be tried either by a jury at Crown Court or summarily, by magistrates.
The change would speed up the court process, cut costs and benefit defendants, who usually got lighter sentences in magistrates' courts, the Home Secretary told the Institute for Public Policy Research in London.
He also rejected the argument that black and Asian defendants would be disproportionately affected by the measure because they elected to go for jury trial more often than their white counterparts.
The evidence showed no difference in the way black people were treated by magistrates or the Crown Court, Mr Straw said.
Research also suggested that magistrates were more likely to acquit black defendants.
Mr Straw, who was delivering the heavily-trailed speech which had been billed as a hard-hitting attack on "Hampstead liberals", criticised "woolly- minded" lawyers whom he accused of "knee-jerk" resistance to all legal reforms.
But he targeted his severest criticism at a cross-party group of peers attempting to wreck the measure when it goes into committee stage in the House of Lords next week.
"I'm not predicting what view the Lords are going to take," Mr Straw said. "But the arguments in favour of this change are overwhelming and it has to be a matter for the elected House of Commons.
"We were elected to modernise the criminal justice system. This is an important part of our manifesto commitment, and for the Lords to prevent the Bill even being discussed by the Commons would be profoundly undemocratic."
His comments did little to win over opponents. A spokesman for the Bar Council, which represents barristers, said: "Jack Straw is becoming even more of a head-banger with criminal justice policy than his predecessor Michael Howard."