Sen. Elizabeth Warren (D-MA) reportedly has the most momentum on the ground in key early states.

FiveThirtyEight has been interviewing activists since December, and on Tuesday the outlet revealed that these activists are indicating that Warren “is the only candidate on a clear upward trajectory”:

Since December, I have also asked respondents which candidate they think Democrats active in their communities lean toward, regardless of their own preferences. I haven’t published the results for this question before, as estimates for have bounced around a lot, but in this survey I noticed that Warren is the only candidate on a clear upward trajectory. In my first three surveys from December to April, few respondents thought that Democrats in their area were leaning toward Warren. But by June, five of 28 (18 percent) activists I spoke to said people in their community were leaning toward Warren. And this month, nine of 27 (33 percent) said they thought people in their community were leaning toward Warren, putting her well ahead of all other candidates. This tracks with her rise in recent polling and her strong showing in some early voting states. So even though no activist has committed to Warren, they now seem to view her candidacy as viable and believe it has momentum.

Last week, Republicans and Democrats praised Warren’s strong ground game in Iowa and Nevada, two early caucus states where, as then-candidate Barack Obama showed in the 2008 election cycle, organization can make all the difference.

In Iowa, a super PAC backing Sen. Joni Ernst (R-IA) noted that their canvassers constantly run into Warren’s campaign.

“Elizabeth Warren has earned her place in the polls,” Our Iowa Values tweeted. “Iowa Values has been running a massive field effort across Iowa since our launch and we have only run into canvassers from one campaign anywhere in the state – Warren for President.”

Elizabeth Warren has earned her place in the polls. Iowa Values has been running a massive field effort across Iowa since our launch and we have only run into canvassers from one campaign anywhere in the state – Warren for President. #iacaucus #iasen https://t.co/B4bFT5Ee1M — Iowa Values (@OurIowaValues) August 19, 2019

In Nevada, former Senate Majority Leader Harry Reid (D-NV) Reid told Vice that Warren’s field operation is “sensational” compared to former Vice President Biden’s “good” field operation and Sen. Kamala Harris’s (D-CA) “great” organization.

“I’ve been impressed with Elizabeth. She is not hiring a bunch of pollsters and consultants. Everything she’s doing is in-house,” Reid reportedly added. “I’m not going to endorse anyone until after the caucuses but everyone has to be impressed with what she’s doing.”

According to the RealClearPolitics average of the polls, Warren is in second place in Nevada and Iowa and third place in New Hampshire and South Carolina.