Bernie Sanders has Hillary Clinton's team worried about Iowa.

The New York Times writes that the crowds and unexpectedly strong showing garnered by the Vermont senator are setting off worry among Clinton advisers and allies, who believe Sanders could actually overtake her in Iowa polls by the fall. They even believe he could defeat her in the nation's first nominating contest there. The enthusiasm Sanders has generated has called into question Clinton's early strategy of focusing on a listening tour of small groups and wooing big donors in private settings, the Times writes. "We are worried about him, sure. He will be a serious force for the campaign, and I don't think that will diminish," said Jennifer Palmieri, the Clinton campaign's communications director, on MSNBC's "Morning Joe" on Monday.

Carson's cash: Before Republican presidential hopeful Ben Carson was vying for votes from members of Christian organizations, he was charging them tens of thousands of dollars for speeches. As Politico writes, Carson brought in nearly $2 million delivering inspirational speeches to faith-based groups including Christian high schools and pregnancy centers in 2014. A Politico analysis of his financial disclosure form showed that four of his five most lucrative speeches were at such Christian venues. His speaking fees varied widely, from $12,320 to $48,500, according to the disclosures.

The next liberal cause: The Washington Post's Greg Sargent writes that Senate Democrats will soon roll out a new universal pre-kindergarten proposal. If it gets a vote, he says, it will put members of both parties on the record as to whether they support national action to dramatically expand the availability of child care to poor and working families. The proposal could be paid for by reining in corporate tax breaks, according to the Democrats. Specifically, the program would be funded by scaling back corporate "inversions," in which companies declare their U.S. operations are owned by a subsidiary abroad. That results in profits being shifted to places where they are taxed at lower rates.

Trump workers talk: Donald Trump's recent comments about drug dealers and rapists crossing into the U.S. from Mexico aren't sitting well with some of the workers building a new Trump hotel in downtown Washington. The Washington Post says the job site is laden with tension in the wake of Trump's remarks, since it's Latin American immigrants who are doing the bulk of the work. The Post, in fact, says Trump's company may be relying on some undocumented workers to finish the $200 million hotel, which will sit five blocks from the White House. A Trump spokeswoman said the company and its contractors follow all applicable laws. But some workers said they are now worried about their jobs.

Obama hosting Senate Democrats: President Barack Obama and Senate Democrats will huddle at the White House on Tuesday, the Hill reports. The White House says it will mostly be a social gathering, but the Hill notes it will give Obama a chance to meet with his allies in Congress, who have a long to-do list this month. The partisan standoff over government spending is one potential topic of discussion, and the White House is also expected to lean heavily on Senate Democrats to support a nuclear agreement with Iran if a deal is reached this week.