The District of Columbia is an example of a jurisdiction where anyone with a law degree from a non ABA approved jurisdiction, including one from Australia, Canada, etc could qualify by obtaining an LLM from an a school with an ABA approved JD program. Having a foreign LLB from a country with English common law does not work in DC the way it does in NY.
True. But if you are a member in good standing of any other State bar for 5 years, then DC waives the exam, and you can directly get admitted to the DC bar. The same goes for States like Massachusetts, Michigan, Ohio, Vermont, Washington and Wisconsin. For some of these States like Washington, 3 years may be enough to waive the bar exam and get admitted to their jurisdiction.
Most foreign lawyers take the NY or California bar exams. Although the California bar exam is longer and some say harder, some lawyers have no choice but to take it, as that's probably the only jurisdiction that allows correspondence degrees for admission (although after some hurdles). From what I remember, New York does not allow correspondence degrees for admission.
The good thing is Patent law is Federal Law. So, admission to any State Bar and the USPTO will suffice to start working as a Patent Attorney.
There is a number of Patent Attorneys in DC law firms that are only admitted to NY or California, and the USPTO. These same attorneys can waive into the DC bar, should they find the need to, after 5 years.
So, if someone is holding a 3-year LLB degree (not by correspondence) from Australia, Canada, New Zealand or UK, and do not have the extra money or time to put into an LLM (which is not cheap), there are some good options available.
Note that English Common Law is practised in the Indian subcontinent, and some other countries as well, but their LLB degrees do not get the same recognition (LLM waiver from some States) as the above mentioned countries do. So, their lawyers have no choice but to invest the additional time and money in a US LLM, even to take the NY bar.
I am in no way against doing an LLM, as I myself plan to do one here in Australia (which by the way, has one of the best Intellectual Property LLMs in the world at the University of Melbourne). But not needing to do a US LLM to become a US Patent Attorney definitely makes it easier for me. As I do not have to worry about investing the additional time or money in a US LLM.