He plea bargained. There was no trial, and he didn’t admit to this. You are just repeating prosecution leaks. I don’t find what he admitted to at all defensible. But I don’t believe that prosecution leaks deserve much credence, regardless of the target.
As you may know, according to the US Constitution, “Treason against the United States, shall consist only in levying war against them, or in adhering to their enemies, giving them aid and comfort.”
Personally, I think that there’s a more than reasonable doubt that Israel – and South Africa, and Pakistan – are enemies of the United States. To prove to me that someone committed treason beyond a reasonable doubt, show me a declaration of war against alleged enemy. I guess I could consider convicting a US citizen of treason if they were involved in shooting Americans in an undeclared war. But spying for Israel, or China, or Pakistan, or Russia, or, for that matter, the old USSR, isn’t treason.
An interesting, albeit academic, question may be whether people who fancy themselves respecters of the US constitution can call the crime of treason by a different name – say, espionage – set a treason-length sentence for it, and ignore the constitutional treason definition.
Even in the world leader for draconian sentences, the United States, thirty years for spying for a country that is more or less an ally was, AFAIK, an unprecedented sentence. The Justice Department got him to agree to it by saying that otherwise his then-wife would get her own draconian sentence (instead she served, I believe, about thirty months).
I suppose that Pollard is guilty. But if prosecutors were threatening to give my wife a draconian sentence, maybe I’d admit to anything. When the prosecution engages in those kind of threats, the right to a trial is basically dead.
Are there worse examples of draconian American sentencing practices? Definitely. The execution of Ethel Rosenberg, who had a secondary role in the nuclear spying, is one. For more recent non-espionage examples, see: