Seattle - The Seattle judge derided by President Donald Trump on Twitter on Saturday after blocking Trump's executive order on immigration is known for his conservative legal views, for a record of helping disadvantaged children that includes fostering six of them, and for dramatically declaring "black lives matter" during a hearing on police reform in 2015.Judge James L Robart, 69, was appointed to the bench by President George W Bush in 2004, following a distinguished 30-year career in private practice that included his selection to the American College of Trial Lawyers, an honour bestowed on less than 1% of lawyers.The judge made the most high-profile ruling of his tenure on Friday when he temporarily invalidated Trump's ban on travel to the US from seven primarily Muslim nations. Washington state sued to block the order - with support from Minnesota and major corporations including Microsoft, Amazon and Expedia - arguing that it's unconstitutional and would harm its residents, and Robart held that the state was likely correct.The ruling did not sit well with the president. "The opinion of this so-called judge, which essentially takes law-enforcement away from our country, is ridiculous and will be overturned," Trump tweeted.It's a comment unlikely to sway Robart, said those who know him."Jim will give a wry smile, maybe adjust his bowtie a little bit and go back to doing his business," said former Seattle US attorney John McKay, who worked with Robart for a decade at the law firm of Lane Powell Spears Lubersky. "He's a very careful judge, and he's conservative in the sense he looks at the law and tries to determine what that is, not what he wants. He's conservative in his review of the law, but courageous in his application of it."Another former Seattle US attorney, Jenny Durkan, called Robart exacting: "We won some in front of him, and we lost some in front of him. But we knew anytime we walked into his courtroom we'd better be prepared."That was evident on Friday when Robart grilled a Justice Department lawyer, asking if there had been any terrorist attacks by people from the seven counties since the September 11 attacks. Bennett said she didn't know."The answer is none," Robart said. "You're here arguing we have to protect from these individuals from these countries, and there's no support for that."Robart, a graduate of Georgetown Law School, is an expert in patent and intellectual property law. He issued a landmark decision - later upheld by the 9th US Circuit Court of Appeals - in a lawsuit between Microsoft and Motorola that provided guidance in how to calculate reasonable rates for use of another company's patents.He's considered a tough sentencing judge in criminal matters, especially in cases involving white-collar defendants. He has overseen reforms at the Seattle Police Department since 2012, when it agreed to make changes in response to Justice Department findings that its officers were too quick to use force, especially in low-level situations.'Black lives matter'Robart was holding a hearing in that case in summer 2015 - a time fraught with tension over violence by and against police officers around the country - when he surprised the courtroom by adopting the mantra of protesters."The importance of this issue to me is best demonstrated by the news," he said, shaking his head and sighing heavily. "According to FBI statistics, police shootings resulting in death involve 41% black people, despite being only 20% of the population living in those cities. Forty-one percent of the casualties, 20% of the population: Black lives matter."Robart donated to the state Republican party and to GOP candidates before becoming a judge, but he was picked for the bench with the help of a bipartisan selection panel. He helped lead his law firm's efforts to provide free legal services to those who couldn't afford them, and he served as president of Seattle Children's Home, which offers mental health services and special education for at-risk children.And as US Senator Patty Murray noted during his confirmation hearing, he and his wife had fostered six children themselves.Robart drew high praise from Republican Senator Orrin Hatch of Utah, who cited his "exceptional qualifications" and his work representing southeast Asian refugees."Working with people who have an immediate need and an immediate problem that you are able to help with is the most satisfying aspect of the practice of law," Robart said then."If I am fortunate enough to be confirmed by the Senate, I will take that experience to the courtroom with me, recognise that you need to treat everyone with dignity and with respect, and to engage them so that when they leave the courtroom they feel like they had a fair trial and that they were treated as a participant in the system."