Hillary Clinton’s artificially inflated poll numbers have made her seem like an especially strong presidential candidate, but the Clinton bubble is quickly coming to an end.

Earlier in June, Ross Douthat of The New York Times noted that she has been “leading every potential Republican candidate by around 10 points” and “running far ahead of President Obama’s job approval numbers.” Carl Cannon, the Real Clear Politics Washington bureau chief, cited her standing as the most admired woman in America, a contest in which she easily topped Oprah in 2013.

But Ms. Clinton’s re-entry on the political stage over the last few weeks is turning her back into what she was before her stint as Secretary of State: an intensely polarizing political figure. Politico’s most recent poll, conducted in June amid the initial publicity for her book “Hard Choices,” found that her favorability ratings have already dropped by 20 points since 2012 among Republicans.