WASHINGTON -- Bernie Sanders and Elizabeth Warren are Senate colleagues, ideological partners and mutual admirers.
But their tacit alliance in the 2020 Democratic presidential primary is approaching a breaking point as they vie to become the progressive alternative to front-runner Joe Biden.
More than five months out from the Iowa caucuses, liberals are thrilled that two of their own are at the top of the field. But there's an underlying worry among some of their supporters that if both Sanders' and Warren's strength endures, they could clear the path for the more moderate Biden to win the nomination -- a scenario similar to how Republicans never united behind a single alternative to Donald Trump in the 2016 primary.
"We could see ourselves in a very similar position this year with the not-Joe Biden vote similarly diluted and he could win victories with 20 or 25% because all of the vote is spread out," said Tim Smith, a New Hampshire state lawmaker supporting Sanders, but reserving Warren as his second choice. "They have an enormous amount of overlap in terms of the voters they're appealing to."
While the Sanders and Warren campaigns are sensitive to any hint of a burgeoning rivalry, their supporters know their detente can't last much longer. They acknowledge that eventually the two candidates will be forced to contrast their records, policy proposals and plans to defeat Trump.
"I think there's going to be a reckoning," said Ed Butler, a New Hampshire state legislator who endorsed Warren in June and has never been drawn to Sanders. "I think that his positions are valuable, but to me Bernie's always been somebody who says the same thing over and over and over about the 1%, but I haven't heard the back-up. Whereas with Elizabeth, you hear the back-up and the policy and the plan repeatedly, and it's upfront and debatable."
The low-boiling rivalry is expected to come to a head in New Hampshire, the second contest on the nominating calendar. Given both Warren's and Sanders' geographic proximity to the state, a loss there would be difficult for either of them to recover from. A recent Boston Globe/Suffolk University poll showed Biden leading in New Hampshire with 21%, followed by Sanders with 17% and Warren with 14%.
Yet in Iowa, two of the last three polls have shown Warren surpassing Sanders. A new Monmouth University survey in the state showed Warren in second place to Biden, and Sanders falling to fourth place behind Kamala Harris.
In that Monmouth poll, Warren boasted the highest net favorability of any candidate. She also posted an 18-point lead over Sanders among very liberal caucusgoers.
Tim Bottaro, a Sioux City, Iowa, attorney who is supporting Pete Buttigieg as a result of his daughter's employment with that campaign, said Warren has the best organized operation in the state and thinks she's stealing Sanders' thunder on a number of issues.