The personal liberty laws did not violate the constitution. Rather, they described due process for state authorities, and the SCOTUS had resolved the controversy as to the role of the state official in returning fugitive slaves, to wit, there was no role.
So that controversy was settled, and as a matter of “STATES RIGHTS” slave states had no grounds to demand state officials participate in the return of those pretended to be fugitives.
There is an interesting footnote that addresses this in the book "Abraham Lincoln: A History, Volume 3" by Lincoln's two secretaries, John G. Nicolay and John Hay. It says that the personal liberty laws of Vermont, Massachusetts, Michigan, and Wisconsin interfere with the federal law and are thus unconstitutional. Here is a link to the page with the footnote: Nicolay and Hay
Some distinguished lawyers and judges from Massachusetts agreed in the case of Massachusetts. From the Philadelphia Public Ledger of December 20, 1860:
THE CITIZENS OF MASSACHUSETTS AND THE PERSONAL LIBERTY BILLS
Chief Justice Shaw, B. R. Curtis, Joel Parker, and other citizens of Massachusetts equally distinguished, have addressed a letter to the people of that State on the Personal Liberty Bills, which they declare to be unconstitutional. They urge strongly the repeal of them and say:
... We would repeal them under our own love of right; under our own sense of sacredness of compacts; ...
... we firmly believe that the men from whom the worst consequences to our country and ourselves are likely to proceed, have no wish that these laws should be repealed, and no disposition to use any threats in reference to them. On the contrary, they desire to have them stand as conspicuous and palpable breaches of the national compact by ourselves ...
Shaw was Chief Justice of the Massachusetts Supreme Court. Curtis was a former Associate Justice of the US Supreme Court who resigned in protest of the Dred Scott decision. Parker was professor of constitutional law at Harvard and former Chief Justice of the New Hampshire Supreme Court.
The last slave returned to its owner from Massachusetts was in 1854.
Here is what the Michigan legislature and the Detroit Free Press said about Michigan's personal liberty law. From March 2, 1861, issue of the State Gazette of Austin, Texas quoting an article from the Detroit Free Press [italics theirs, paragraph break and emphasis mine]:
Absurd and Impudent Action by the Michigan Legislature
We can conceive of nothing more absurd than the passage by either house of the Legislature, at Lansing, of the resolutions which are reported to have passed concerning national affairs, while the personal liberty bill still stands. The personal liberty law -- so the legislature of 1859 construed it, and such is the only construction which it will bear -- "was designed to and if faithfully executed will prevent the delivering up of fugitive slaves." It is therefore plain, palpable, unadulterated nullification of the fugitive slave law.
Michigan, for six years past, has stood in the attitude of open and avowed hostility to the authority of the Constitution of the United States. Until she has changed this attitude -- until she has hauled down the flag of rebellion -- until she is fully within the line of her constitutional duty -- how absurd is it, how impudent is it, in her to pass resolutions that the Constitution of the United States, and all laws in pursuance thereof, "are the supreme law of the land" -- that "there is no method for a State, or the citizens of a State, to escape the obligations imposed by the Constitution except by and through an amendment of that instrument" -- that "Michigan is now, as she has always been, entirely loyal to the Constitution;"
... We know of nothing better calculated to stimulate secession than this action, especially as it is the action of a State whose professions of loyalty to the Constitution are a lie. -- Detroit Free Press