So far, it seems, Sen. Bernie Sanders' (I-Vt.) early campaigning is paying off.

The latest Iowa caucus poll conducted by the Des Moines Register, CNN, and Mediacom shows former Vice President Joe Biden leading the field of 2020 Democratic presidential candidates. Although Biden has yet to announce that he will even run, he earned the support of 27 percent of those polled. But Sanders, who was in Des Moines on Saturday, was close behind at 25 percent.

No other candidate even breached double digits. Sens. Elizabeth Warren (D-Mass.) and Kamala Harris (D-Calif.) were next in line at 9 and 7 percent, respectively. Former Rep. Beto O'Rourke (D-Texas), who like Biden has yet to announce his candidacy, and Sens. Cory Booker (D-N.J.) and Amy Klobuchar (D-Minn.) were the only other names to rise above 1 percent.

Biden and Sanders led in the last caucus poll in December, as well. Though at that time, Biden held a 13-point advantage over Sanders.

Per CNN, the Poll was conducted by Selzer and Co. in Des Moines from last Sunday through Wednesday among a random sample of 401 likely Democratic caucus-goers. The questioning took place over the phone. The margin for error is plus or minus 4.9 percentage points.