Dianne Feinstein, who’s represented California in the U.S. Senate since 1992, isn’t going to have the smooth reelection she might have hoped for. Reports are surfacing that Kevin de Leon, president of the California state senate, will challenge her in the state’s primary,California holds an all-parties primary.

‘>¹ and Feinstein might have reason to be worried.

As we’ve noted recently, the idea that Feinstein would face a primary challenge isn’t a total shock. During the first year of the Trump administration, Feinstein has been singled out by her liberal constituents for being too conservative for their taste. She’s been booed by them at town hall events and a late March poll of California adults showed that Feinstein’s approval rating had slipped 7 percentage points from the previous year, to 49 percent.

Feinstein is feeling the heat in part because her more liberal constituents are correct in surmising that she is more conservative — relative to the politics of the state she represents — than other Democrats. Feinstein has voted in support of President Trump’s agenda about 31 percent of the time, according to our “Trump score.” Ten Democrats have voted with Trump more. But because California is so liberal — Trump lost there by 30 percentage points in 2016 — we’d expect Feinstein to vote in line with the Trump position just 19 percent of the time. That’s a bigger pro-Trump gap than any other Democrat in the Senate.

California just passed legislation to become a “sanctuary state,” a move that’s been met with displeasure by the Trump administration. De Leon seems likely to play up the state’s need to assert itself as a powerful bloc of resistance to Trump. In recent weeks, local news sources have noted de Leon’s rebukes of Feinstein, whom he paints as sympathetic to Trump.

In August, after Feinstein said Trump “can be a good president” if he were to “learn and change,” de Leon hit back, saying, “It is the responsibility of Congress to hold him accountable — especially Democrats, not be complicit in his reckless behavior.” Most recently, de Leon pushed back against Feinstein’s comments that the recent massacre in Las Vegas couldn’t have been prevented by changes in gun laws because the shooter had passed background checks.

Feinstein is supported by national Democrats like House Minority Leader Nancy Pelosi and fellow California Sen. Kamala Harris, but she reportedly pushed up the announcement that she would run for reelection to this week out of worry that de Leon would announce soon. After Feinstein’s reelection announcement, Rep. Ro Khanna said that Feinstein was “out of touch” and that it was time for Democrats to “move on” from the 84-year-old Senator. Khanna, for his part, floated not de Leon, but Rep. Barbara Lee or former Labor Secretary Robert Reich as possible alternatives.

Whomever jumps into the race, Feinstein’s 2018 looks like anything but smooth sailing.