Sen. Richard Blumenthal, D-Conn., accompanied by fellow Senate Democrats, and speak during a news conference on Capitol Hill in Washington, Tuesday, March 17, 2015, calling for a vote on the nomination of Loretta Lynch to become the 83rd Attorney General U.S. Photo: Lauren Victoria Burke, AP Photo/Lauren Victoria Burke

A tough slog ahead for Connecticut Republicans -- challenging Democrat Richard Blumenthal in 2016 -- just got more daunting.

The first-term U.S. senator raised more than $1 million during the first three months of the year for his re-election bid from a Rolodex full of household names that include Dick Gephardt,Harold Ickes, Anna Quindlen and two of George Soros' sons.

And a nine-time Grammy winner: trumpet impresario Herb Alpert.

Blumenthal, 69, who was ranked the eighth wealthiest member of Congress this year by Roll Call, is sitting on $1.6 million cash, according to his April 15 filing with the Federal Election Commission.

The 571-page report provides a detailed glimpse at the sphere of influence and connections of Blumenthal, whose first-quarter haul was augmented by dozens of contributions from lawyers around the country and from industries that have a vested interest in his work in the Senate. They include unions for railroad workers, defense contractors, financial services firms and the Mohegan Tribe, one of two casino operators in the state.

"I'm energized by a strong start and broad base of support," Blumenthal said Friday.

So far, no Republicans have stepped forward to run against Blumenthal, whose approval rating was 64 percent in a March 12 Quinnipiac University Poll. But that didn't stop state GOP Chairman Jerry Labriola Jr. from trying to cast the former state attorney general as being beholden to special interests.

"We know what Dick Blumenthal has been doing for the last five years -- doing favors for Washington insiders," Labriola said. "Now they are paying him back. More than ever, Connecticut needs a new voice in Washington."

"I'm energized by a strong start and broad base of support," Blumenthal said Friday.

So far, no Republicans have stepped forward to run against Blumenthal, whose approval rating was 64 percent in a March 12 Quinnipiac University Poll. But that didn't stop state GOP Chairman Jerry Labriola Jr. from trying to cast the former state attorney general as being beholden to special interests.

"We know what Dick Blumenthal has been doing for the last five years -- doing favors for Washington insiders," Labriola said. "Now they are paying him back. More than ever, Connecticut needs a new voice in Washington."