Democrats looking to build a case against President Donald Trump ahead of next month’s elections have begun using dissident journalist Jamal Khashoggi’s mysterious disappearance at the Saudi consulate in Istanbul as ammunition.

Sen. Bernie Sanders, I-Vt., attacked Trump today over his cozy relationship with Riyadh, which he argues enabled Khashoggi’s alleged murder along with other exactions by Saudi Arabia. A favorite among left-wing voters and a possible 2020 presidential contender, Sanders is on a nine-state campaign tour this month to fire up the base for Democratic mid-term candidates.

“If the Saudi regime murdered a journalist critic in their own consulate, there must be accountability and there must be an unequivocal condemnation by the United States,” Sanders said in a foreign policy address at Johns Hopkins University in Washington. “But it seems clear that Saudi Crown Prince Mohammad bin Salman feels emboldened by the Trump administration’s unquestioning support.”

Why it matters: Saudi Arabia can’t afford another black eye in its relationship with the United States. While the oil-rich kingdom is spending millions of dollars to paint the crown prince as a reformist moderate, Congress is increasingly concerned over the humanitarian impact of the US-backed Saudi-led war in Yemen while Trump himself has ripped Riyadh amid rising oil prices.