Clarence Thomas is not trying to uphold "the original meaning of the Constitution". He is trying to impose his own personal social and political ideas, no matter how he tries to camouflage his Right-Wing views in Conservative legal jargon.
In the original Constitution, there was no provision for the Supreme Court to rule laws of Congress unconstitutional. That power was created for the Supreme Court in an 1803 decision by the first great judicial activist, Chief Justice John Marshall. Does Clarence Thomas want to go back to the "original Constitution" and eliminate the Court's power to rule any laws unconstitutional?
The "original Constitution" allowed slavery and said that a black man counted as only 3/5 of a person. Does Thomas want to revert to those portions of the "original Constitution"?
In 1858, the discredited Dred Scott decision said that, according to the "original Constitution", a slave was property, and a runaway slave had to be returned to his master. Does Thomas want to return to that part of the "original Constitution"?
The "original Constitution" had a very narrowly interpreted interstate commerce clause and, accordingly, many early New Deal laws of 1933 and 1934 were struck down as unconstitutional by the Conservative Supreme Court of the early 30's. Does Thomas want to revert to that narrow interpretation which would allow so much of today's social legislation to be overturned?
For a "non-activist" Justice, Thomas was one of the prime movers in the notorious Bush v. Gore decision of 2000 (probably the Court's worst decision ever, along with Dred Scott), in which the US Supreme Court took away from the Florida Supreme Court the power to set the rules for counting the votes in the State of Florida, thus preventing all of Florida's votes from being counted. As a result, the presidential election of 2000 was decided without all the votes having been counted. Just as in Fascist countries, the president in 2000 was appointed by the Supreme Court, not elected by all the voters.
In other words, this "strict Constitutionalist" can be a very activist Justice when it suits him. His talk about following the "original Constitution" is a smokescreen. Thomas always follows his rock-ribbed Conservative ideology, wherever it might lead him.