One of the seven Republican senators who voted to convict Donald Trump at his second impeachment trial warned on Sunday that the former president’s “bullying” of the party would lead to electoral defeat in next year’s midterms and beyond.

Bill Cassidy of Louisiana was speaking days after the Ohio Republican congressman Anthony Gonzalez, who voted to impeach Trump over the US Capitol attack, announced he would not seek re-election.

On Saturday another Trump critic in the House, Adam Kinzinger of Illinois, released a hard-hitting video statement in which he told colleagues “silent” about the state of their party the “time for hiding is over”.

Cassidy told NBC’s Meet the Press: “Politicians are not victims. Politicians make a choice. If we choose to look forward, bringing positive solutions to the American people who have needs, we win. If we choose to be bullied, we lose.”

The two-term senator also appeared to reference an extraordinary letter sent this week by Trump to the Georgia secretary of state, Brad Raffensperger, demanding he decertify the “illegitimate” presidential election result.

Joe Biden’s win in Georgia is central to Trump’s big lie that the election was stolen. His previous efforts to overturn the result are the subject of a criminal inquiry.

“The broader question, frankly, is do Republicans continue to re-litigate 2020, or do we look forward with a positive agenda?” Cassidy said.

“If we re-litigate 2020 over and over again it won’t change the result in 2020 but we’re sure to lose in 2024. On the other hand, if we have a positive agenda, which addresses the fact that the Biden administration is in disarray, whether it’s inflation, the border, Afghanistan, then the country will win and we’ll win.

“But if we choose to be bullied, we’ll lose.”

Allies of Trump have said they expect him to run for the White House again. Cassidy’s vote to convict him would have disqualified the former president from running for office again. It brought a fierce backlash from members of his own party and Trump himself. But the Louisiana senator does not face reelection himself until 2026.

Others who have spoken out have felt the wrath of Trump and his acolytes, including Liz Cheney, the Wyoming congresswoman ousted as No3 Republican in the House after voting for impeachment, and Gonzalez.

Gonzalez, a 37-year-old former NFL player, said he was standing down to spend more time with his family. But he acknowledged that “toxic dynamics inside our own party” was also a significant factor.

In a New York Times interview, Gonzalez said Trump was “a cancer for our country” whom he did not believe could ever be president again. He also dismissed Trump’s inevitable “good riddance” response, voiced in a statement on Friday.

“I haven’t cared what he says or thinks since 6 January, outside when he continues to lie about the election, which I have a problem with,” Gonzalez said.

Cassidy would not be drawn on whether Gonzalez’s departure was good or bad for the party.

“Anthony is choosing his personal priorities. You read his statement, it stands for itself,” he said. But he stressed that the GOP was in dire need of a new direction.

“We answer to voters. And so if we don’t answer to voters in a positive way, we lose,” he said. “If all you do is talk about the past, you’re yesterday’s news.”