I put this in Before 1900 although it would have consequences After 1900 as well.
What if the USA had no constitutionally-entreched Bill of Rights? There would still be a Bill of Rights but it would be statutory (created by Congress) and be able to be overridden by a complex process if the government were determined to. Or alternatively the Bill of Rights could still be constitutionally-entrenched BUT it could have a Notwithstanding clause like in Canada allowing the courts to be overriden in rare circumstances.
Just for information sake, in the UK for instance (well, this is my understanding of it) with their Human Rights Act, the judiciary can declare a law to inconsistent with the Act. The government then has to either change the law to be consistent with the Act or has to re-pass the legislation throught Parliament and explicitly declare that it violate the Human Rights Act.
Also all new legislation must declare that it is either consistent or inconsistent with the Human Rights Act.
The idea of all this being that in democratic societies such as the UK or USA, even relatively authoritarian governments are loathe to be seen as openly violating human rights even when they are technically able to. This gives the courts a defacto power to quash legislation.
How would such an ATL alter US political history?
What POD would be needed for this to occur. Admittedly this is the hard bit of this ATL, as the reason for statutory Bills of Rights and Notwithstadning clauses in other nations is actually a reaction to what are perceived as excessive judicial power in the USA, so it would be hard to see how the idea would first arise in the USA. Any ideas?