U.S. Sen. Chris Murphy accepted the Democratic nomination for a second term Friday with a speech framing the 2018 election up and down the ballot as an existential battle for control of Hartford and Washington with a Republican Party that has lost its compass with President Donald Trump at the helm. 

Murphy, 44, a national voice on gun control who has worked with varying degrees of success to shape the nominations for governor and Congress, symbolically spoke after Gov. Dannel P. Malloy exited the Connecticut Convention Center in Hartford, ending eight years as the leader of a Democratic Party crowded at the State Capitol by a resurgent GOP. 

Nominated by acclamation, Murphy turned from his own re-election to some of the tensions in his party, which faces a potential floor fight Saturday over gubernatorial candidate Ned Lamont's choice of Susan Bysiewicz as a running mate, instead of a black or Hispanic candidate. 

On a voice vote earlier Friday, the convention rejected an effort to amend the party rules to implement an affirmative action policy, which would require convention delegations to reflect the racial makeup of their communities and have equal numbers of men and women. 

"I just don't want you to be pulled apart from each other by all the fissure lines that can sometimes run through our party, because the stakes are too high, right? Donald Trump presents this real, everyday, unique, present threat to our democracy," Murphy said. 

Since his election in 2016, Trump has been the Democrats' best recruiter, bringing out volunteers and candidates that propelled the party to unexpected wins in municipal races in Connecticut, a blue state in presidential and congressional elections, but one that has been trending purple to red in state races. 

"What you saw in November was a surge in turnout," Murphy told reporters before the convention opened. "I think you're going to see the same thing this November. I think our candidate for governor is going to put forward a plan on how to keep Connecticut's economy moving in the right direction, and I think Democrats are going to turn out and respond." 

After ceding supermajorities to the Democrats in the 2008 wave led by President Barack Obama, Republicans have tied Democrats in the state Senate and grown from 37 seats in the House to 71, just five short of a majority. The GOP has not won control of both chambers of the General Assembly since the Ronald Reagan landslide of 1984. 

"Connecticut Republicans, they can taste control of the legislature and the governor's office. They have never been closer to seizing control of the agenda," Murphy told delegates. "And just remember, guys, this isn't your father's Republican Party any more here in Connecticut. This is the party of Trump. This is the party of the Tea Party. If they take over Hartford, all of the protections that we have here today from the worst of America First, they come crumbling down. We cannot let that happen." 

The delegates applauded. 

"And so, this is a big moment. This is a big moment," Murphy said. "And though we're going to have our squabbles, you've got to remind yourselves — all these things that bind us together. Why you are here. Why you have chosen to give such a big part of yourself to this cause. Why you are doing this and not something else." 

Before he took the stage, the Democrats played a film, a collection of his greatest hits on MSNBC and other television networks, a reminder of his place on the political stage in Washington. One of the clips showed his annual walk across the state, an event that draws media attention and opens him to unexpected encounters with voters, such the man he met walking past a pawn shop in Meriden last year. 

He began the walk the day after a car plowed into a crowd of people demonstrating against a gathering of white nationalists in Charlottesville, Va. On Friday, he took to the stage hours after a teenager shot 10 people to death in a high school near Houston. 

"We're Democrats, because we want every child in this country to grow up without fear of gun violence," Murphy said. 

"We support the Second Amendment as Democrats, but we support the real Second Amendment, not the imagined Second Amendments," Murphy said. "We support the Second Amendment that allows Congress to do what the overwhelming majority of Americans wants us to do, like pass mandatory background checks and ban assault weapons." 

It was another applause line.

Earlier, Malloy mixed a heartfelt farewell with an impassioned appeal to combat the policies of Trump to open the Democratic State Convention.

The governor, who is not seeking re-election after two terms, said control of Congress and the General Assembly is crucial to preserve values protecting women, minorities, immigrants and working-class families, as well as public safety.

"Democrats don't worry about how rich they can make their friend," Malloy told the delegates. "They worry about how they can make their community richer ... how they can spread the wealth as opposed to bringing it all in."

The desire to help others "is part of our DNA," Malloy said.

Connecticut embraced participation in the Affordable Care Act while Republicans in Washington "plot to take away health care for tens of millions," Malloy said.

The state was the first to raise the minimum wage to $10 per hour. "We should raise the minimum wage again and again and again," the governor said. "It is the number one tool for lifting people out of poverty."

Keith M. Phaneuf of the Connecticut Mirror contributed to this report.