Longtime Rep. Peter King (R-N.Y.) could be in danger of losing his re-election.

While the 13-term Republican representative is still the heavy favorite, election forecast website FiveThirtyEight lowered his odds of winning by about 10 points on Monday. Analyst Nate Silver chalked the shift up to good Democratic fundraising.

King's Democratic opponent, Liuba Grechen Shirley, raised more than King's last five opponents combined, The New York Times reported in August, and Grechen Shirley told Newsday in September that she outraised King by $25,000 in the last quarter.

Grechen Shirley now has a 26.9 percent chance of defeating King, based on FiveThirtyEight's model. For comparison, the same forecast gave President Trump a 28 percent chance of being elected in 2016.

This shift comes after the Cook Political Report moved King's seat from being "safe Republican" to "likely Republican" in September. The New York Times reported last month that Republican and Democratic strategists both felt King "might not be safe," especially after his district was redrawn in 2012 to include more registered Democrats than Republicans. Grechen Shirley, who has never held elected office, told the Times that she believes she can pull off an Alexandria Ocasio-Cortez-style upset.

Even if King does end up winning, as he is still likely to do, this could end up being the closest re-election of his career. FiveThirtyEight, after all, predicts he will receive 52 percent of the vote while Grechen Shirley will receive 48 percent. In 2016, King defeated his Democratic opponent by a margin of more than 20 points. Brendan Morrow