WASHINGTON (MarketWatch) — Bernie Sanders has got Hillary Clinton insiders concerned.

Politico writes it is Vermont Sen. Sanders, not former Maryland Gov. Martin O’Malley, who Democratic strategists and Clinton insiders expect will pose a bigger threat to the former secretary of state as she seeks her party’s presidential nomination. Insiders familiar with the Clinton campaign’s thinking described it as “frightened” of Sanders, Politico wrote — not that he would win the nomination, but that he could damage her with the activist base by challenging her on core progressive positions in debates and make her look like a centrist or corporatist. Sanders has declared his candidacy; O’Malley is expected to later this week.

Clinton hits Paul, Rubio, Walker:Hillary Clinton is going after Republican presidential hopefuls Rand Paul, Marco Rubio and Scott Walker on the subject of equal pay. National Journal writes Clinton did not say their names at an event in South Carolina on Wednesday, but it was clear from quotes she used who she was talking about. “One Republican candidate for president dismissed equal pay as a ‘bogus issue.’ Another said Congress was ‘wasting time’ worrying about it. One even said that efforts to guarantee fair pay reminded him of the Soviet Union.” Clinton added: “And to that I say, what century are they living in?” The first quote comes from Walker, the second from Rubio and the third from Paul. Walker is expected to run for president but has not formally declared his intentions; Rubio and Paul have announced their campaigns.

Bush’s boards: During his transition from Florida governor to likely presidential candidate, Jeb Bush served on the boards or as an adviser to at least 15 companies and nonprofits, the Associated Press writes. The array of corporate connections earned Bush millions of dollars as well as occasional headaches. His experience on boards could evolve into a theme during the 2016 race for the presidency, AP writes. One issue the Republican could be asked to explain: at least five companies where he served on the board or as an adviser faced class-action lawsuits from shareholders or legal action by the government.

Americans back trade deals:A majority of Americans support new international trade agreements, according to a Reuters/Ipsos poll. The showing of support comes even as President Barack Obama struggles to win support for legislation key to sealing a Pacific Rim trade deal. Unions and anti-trade activists are pressuring lawmakers in the House of Representatives to vote against so-called fast-track authority, which Obama wants in order to complete the 12-nation Trans-Pacific Partnership. The poll, meanwhile, found 56% of Americans support new trade deals to promote the sale of U.S. goods overseas, and just 13% were opposed.

Trumka on trade:AFL-CIO President Richard Trumka, an opponent of both fast track and the TPP, told USA Today there will be costs for Hillary Clinton if she backs either one. “It will be tougher to mobilize working people,” he said. “It’ll be tougher to get them to come out excited and work to do door-knocking and leafleting and phone-banking and all the things that are going to be necessary if she is the candidate and we endorse her to get elected. It will make it far more difficult.”