WASHINGTON — Democrats swept a rules package for their impeachment probe of President Donald Trump through a divided House on Thursday, as the chamber’s first vote on the investigation highlighted the partisan breach the issue has only deepened.

By 232-196, lawmakers approved the procedures they’ll follow as weeks of closed-door interviews with witnesses evolve into public committee hearings and — almost certainly — votes on whether the House should recommend Trump’s removal.

All voting Republicans opposed the package. Every voting Democrat but two supported it.

Underscoring the pressure Trump has heaped on his party’s lawmakers, he tweeted, “Now is the time for Republicans to stand together and defend the leader of their party against these smears.”

Yet the roll call also accentuated how Democrats have rallied behind the impeachment inquiry after House Speaker Nancy Pelosi spent months urging caution until evidence and public support had grown.

She and other Democratic leaders had feared a premature vote would wound the re-election prospects of dozens of their members, including freshmen and lawmakers from Trump-won districts or seats held previously by Republicans. But recent polls have shown voters’ growing receptivity to the investigation and, to a lesser degree, ousting Trump.

That and evidence that House investigators have amassed have helped unify Democrats, including those from GOP areas. Rep. Cindy Axne, D-Iowa, said she was supporting a pathway to giving “the American people the facts they deserve,” while Rep. Andy Kim, D-N.J., said voters warrant “the uninhibited truth.”

Yet Republicans were also buoyed by polling, which has shown that GOP voters stand unflinchingly behind Trump.

“The impeachment-obsessed Democrats just flushed their majority down the toilet,” said Michael McAdams, a spokesman for House Republicans’ campaign arm.

Elsewhere at the Capitol on Thursday, three House panels led by the Intelligence Committee questioned their latest witness into the allegations that led to the impeachment inquiry: that Trump pressured Ukraine to produce dirt on his Democratic political rivals by withholding military aid and an Oval Office meeting craved by the country’s new president.