This question refers to Dove v. Oglesby, a case decided in 1926 ( In it, the Oklahoma Supreme Court ruled that forcing people to rank EVERY candidate violated the constitutional right to “free exercise of the right of suffrage” (voting). Rather than throwing out that aspect of instant runoff voting at that time, the court ruled the entire law invalid.

No, the Oklahoma Supreme Court ruled on an IRV method very different than what we see today and even noted that they have no objection to preferential voting in general but that they saw a major problem with this particular case.

So what happened? In 1925, the Oklahoma Democratic party adopted IRV for its primary elections, but their IRV system did not allow voters to submit a ballot with only one candidate endorsed. In instant runoff elections today, submitting a ballot with only a first choice candidate is sometimes called “bullet voting”, but the 1925 primary law declared these ballots invalid. 

That’s why, in the 1926 Dove v. Oglesby decision, the court wrote that this election process 

“has the undeniable effect of saying to a voter that, unless you vote for one or two who are not your choice, then the vote of the one who is your choice shall not be counted. In other words, you shall not vote at all, unless you vote for one or two who may be wholly objectionable… These restrictions cannot be harmonized with the above constitutional guaranties that ‘No power shall ever interfere to prevent the free exercise of the right of suffrage’”

Does this mean that all IRV is unconstitutional in Oklahoma? No. The OKSC made it clear in their majority opinion that they are open to preferential voting systems like IRV. They wrote: 

The Constitution says, "No power shall ever interfere." It might be well to say, in this connection, that we perceive no constitutional objection to a preferential primary law, provided it does not violate constitutional rights, but the vice in the act in question lies in the fact that the voter is compelled to vote for some one whom he may not want in order to have his vote counted for the one he does want.” 

IRV systems today don't restrict voters by forcing them to rank candidates they don't support. Allowing voters to the opportunity to rank only their endorsed candidates, rank a write-in candidate, or abstain from ranking altogether ensure that modern IRV doesn't infringe on constitutional rights.