A member of President Obama's Cabinet took a shot at President-elect Donald Trump in a late-Christmas-weekend message on social media while alluding to Democratic retribution in the 2018 midterms.

In a pair of tweets Monday, Housing and Urban Development Secretary Julian Castro suggested that the president-elect is lucky to have both houses of Congress under Republican control, or else he might face the wrath of the Democrats and fail to advance his agenda.

Trump is so corrupt that if Democrats controlled even one chamber of Congress, he'd be done before he even got started. #2018 — Julián Castro (@JulianCastro) December 27, 2016



"Trump is so corrupt that if Democrats controlled even one chamber of Congress, he'd be done before he even got started. #2018," Castro wrote.

Castro added that Trump is the "shadiest, most corrupt guy to take the Oval Office," and that he "will have no strong federal checks and balances."

So Trump-- the shadiest, most corrupt guy to take the Oval Office, will have no strong federal checks and balances. Has to change. #2018 — Julián Castro (@JulianCastro) December 27, 2016



The comments come after Obama argued in an interview this weekend that if he could have run for a third term against Trump, he would have won.

Trump has promised to "drain the swamp" once he takes office on Jan. 20, a reference to cleaning up the ethics of the executive branch. However, Trump's critics have accused the Republican of stacking his incoming administration with insiders and lobbyists and possessing potential financial and familial conflicts of interests with his business empire — issues which Trump has made moves to address.

Castro, a rising Hispanic politician in the Democratic Party, was once rumored to be in consideration to be Hillary Clinton's running mate. He served as mayor of San Antonio before joining the Obama administration in 2014. His identical twin brother Joaquin serves as a member of Congress from Texas.

Castro will be succeeded at HUD by former neurosurgeon Ben Carson, who ran against Trump for the Republican presidential nomination.