Former Florida governor Jeb Bush speaks at the First in the Nation GOP summit in New Hampshire. (Darren McCollester, Getty Images)

Former Florida governor Jeb Bush speaks at the First in the Nation GOP summit in New Hampshire. (Darren McCollester, Getty Images)

First, Martin O’Malley and Bernie Sanders. Now, Jeb Bush is training his sights on Hillary Clinton when it comes to trade.

In a lengthy Medium post, the former Florida governor accused Clinton of flip-flopping on the Trans-Pacific Partnership — the massive pact President Obama is negotiating with 11 Asia-Pacific countries.

“I haven’t changed in my view even though Hillary Clinton has. It is time to move forward as even recent Democratic presidents have recognized — and Sec. Clinton shouldn’t stand in the way for political gain,” Bush wrote.

As secretary of State, Clinton said the Trans-Pacific Partnership would set the “gold standard in trade agreements.” In her memoir, Hard Choices, Clinton described the Trans-Pacific Partnership as a “strategic initiative that would strengthen the position of the United States in Asia.”

The fight over “fast-track” authority, which would help the Obama administration reach trade deals, and the Trans-Pacific Partnership has exposed tensions in the Democratic Party between those who support big business and those who support labor unions.

O’Malley, the former Maryland governor, has been unrelenting in recent days with missives about bad trade deals that are clearly meant as a shot at Clinton.

For her part, Clinton hedged in her first public comments on the issue. She didn’t say yesterday whether she was for or against the Trans-Pacific Partnership, but said: “Any trade deal has to produce jobs and raise wages and increase prosperity and protect our security.”

MORE: Elizabeth Warren fires back at Obama on trade