The government doesn't want intelligence agencies reined in by anything but American interests. They want those agencies to be free do commit whatever evil is deemed necessary to further those interests, laws and Constitution be damned. The NSA is still spying on everyone. The CIA still runs torture camps around the world. Nothing changes. Snowden didn't change anything. Assange didn't change anything. Wyden isn't going to change anything.
The ability of the American people to hold their government to account in any meaningful way is a facade. Americans live under the oligarchy of corporations and the military industrial complex, not any kind of functional democracy. The American people, despite their guns and breathless evocations of the Founding Fathers, are not in control.
In the most technical sense it's legal though of course it subverts the entire idea of the justice system by having a court in your pocket.
[1] https://www.vox.com/2015/5/7/8567089/nsa-patriot-act-ruling
[2] https://www.washingtonpost.com/world/national-security/nsa-b...
There is nothing more morally corrosive than a law enforcement agency betraying the trust represented by their powers.
Although that statement is just an oversimplification of the situation. The government should follow domestic law even if it breaks foreign law by design.