"States' rights" is described in Black's Law Dictionary.
" Under the Tenth Amendment, rights neither conferred on the federal government nor forbidden to the states".
He describes the situation using Scott Pruitt's position as Attorney General of Oklahoma arguing against Obamacare compared with his likely positions with respect to EPA regulations to make his case.
"...He was part of a coalition of Republican attorneys general fighting President Barack Obama's health law - better known as Obamacare - based on a core party principle: that states' rights trump federal powers, and that programs like Obamacare represent a radical overreach by the federal government.
Now, as Trump looks to undo Obama's legacy and begin constructing his own, Pruitt and other administration Republicans are showing little interest in protecting states' rights. Instead, they are embracing sweeping new environmental, health care and immigration policies that are to be imposed on all states."
That last sentence is extremely important and indicates that Mr. Levine either does not understand the concept of states' rights or he chooses not to understand it in furtherance of his narrative.
Read this again carefully:
"...coalition of Republican attorneys general fighting President Barack Obama's health law - better known as Obamacare - based on a core party principle: that states' rights trump federal powers, and that programs like Obamacare represent a radical overreach by the federal government."
Apparently Mr. Levine thinks that a core principle of the Republican Party is "that states' rights trump federal powers". Really? A quick look at Article I, Section 8 of the Constitution and the 10th Amendment might be in order.
The actual "core principle" is that the federal government ought not to expand beyond the powers conferred on it by the Constitution. In the quite widely disseminated opinion of every Republican I have ever heard on the subject, Obamacare is indeed a "radical overreach by the federal government" and rolling it back is entirely consistent with the protection of states' rights.
The administration will not (and proclaims it very loudly, I'm surprised Mr. Levine hasn't heard about this) be imposing new environmental, health care and immigration policies on the states in violation of the states' rights principle. They will be rolling back environmental and health care policies that violate states' rights in those areas.
For reasons best known to Mr. Levine he believes that immigration law is a power to be exercised by the states. It is not. To argue otherwise would be to suggest it reasonable and appropriate to have as many as 50 different immigration regimes. Ridiculous on its face. A quick look at Article I, Section 9 of the Constitution might help.
He may recall Arizona's efforts to gain control of its southern border. Arizona's argument was not that it was within the state's rights under the Constitution to assert control over the border. The argument was that the federal government, having completely failed to carry out its obligations with respect to the border, had forfeited its constitutionally mandated jurisdiction over it and Arizona had to step in to protect its sovereignty.
So the "how" is by misunderstanding, misinterpretation, mendacity or some combination of the three.
The "why" is to provide cover for Democrats who have long abhorred the notion of us yokels in the hinterlands making any decisions for ourselves. (New York abortion laws for Mississippi anyone?) Since "everyone" is changing sides there is no shame in it.
They are suddenly embracing the concept, see sanctuary cities . To be fair, there was a time when Democrats fully embraced the notion of states' rights. That was in 1860 when they wrongly and unreasonably asserted the states' rights defense in support of slavery and secession.