(CNN) You would think that with President Donald Trump's approval ratings at historic lows for a first-year president, the candidate he beat in the 2016 election might see a similar improvement in their popularity numbers -- a sort-of buyer's remorse bump.

That has not been the case with Hillary Clinton. In fact, the opposite has been true.

Hillary Clinton's approval dipped to 36% in a December Gallup poll, the lowest mark ever measured for the former senator and first lady in the survey. Her unfavorable ratings -- at 61% -- also marked a new high (or low) for Clinton.

Given how long Clinton has been in public life, it is saying something that she is now at her lowest ebb. It's also somewhat inexplicable given that Clinton's past popularity troughs have been directly tied to times she has been in the heat of a campaign.

Clinton's previous low point in Gallup data, for example, was in late August/early September 2016 -- as that presidential campaign was in full roar. Typically, when Clinton is either out of office or not running for anything, her numbers are significantly better. For the four years that Clinton served as Secretary of State, her approval rating often topped 60%.

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