To be clear, I don't think the cop in this case is protected by qualified immunity. Qualified immunity protects officers from civil liability unless they violate a right whose existence was "'clearly established' at the at the time of the challenged conduct".
Ashcroft v. al-Kidd,
563 U.S. 731, at 733 (2011), quoting
Harlow v. Fitzgerald,
457 U.S. 800, 818 (1982). In most cases, to prove that a right is clearly established, it helps to have an on-point case holding that the particular challenged conduct was unconstitutional.
We have such a case in this instance. The Supreme Court ruled in
Missouri v. McNeely,
569 U.S. 141 (2013) that, in the absence of some kind of exigency, warrantless blood draws are unconstitutional. Of course, exigent circumstances could be common in such situations. For example, if a warrant cannot be acquired before a drunk driver's liver processes the alcohol out of his system, then it may be necessary to draw blood without a warrant.
However, the officer here doesn't seem to have argued that there was any kind of exigency. In fact, he made clear on the video that he didn't think there was probable cause to draw blood in the first place. Probable cause would be required even in exigent circumstances.
The officer's last line of defense was that he was relying on Utah's implied consent law, which had expired in 2007. Were this a reasonable misunderstanding of state law, that defense might work for the officer, as the Supreme Court held in
Heien v. North Carolina,
135 S. Ct. 530 (2014) that a police officer's reasonable mistake of state law does not render a search unreasonable. However, the Supreme Court has provided us with another specific, on point case holding that the officer's challenged conduct was unlawful. The Supreme Court ruled in
Birchfield v. North Dakota,
136 S. Ct. 2160 (2016) that states could not compel warrantless blood tests through implied consent laws.
The defense of qualified immunity has grown pretty strong, but the officer's conduct in this case matched an exact pattern of behavior that the Supreme Court has recently and clearly explained to be unconstitutional. Qualified immunity protects "all but the plainly incompetent or those who knowingly violate the law."
Malley v. Briggs,
475 U.S. 335 (1986). The officer falls into at least one of these categories, if not both.
(I can't speak with as much confidence about the nurse's potential liability and I don't think it's relevant to this case. Maybe she would have been liable for malpractice; maybe she wouldn't have been because duress is a defense; maybe duress isn't a defense but she could seek indemnification from the officer. I don't know enough about the particulars of tort suits to say.)