There are not a lot of votes that could trump spending primary day in Georgia, but two House Republicans fighting for their political lives flew back to Washington to show their support for the Port of Savannah expansion.

U.S. Reps. Phil Gingrey and Jack Kingston, Republicans seeking a U.S. Senate seat, appeared for a long-awaited landslide vote for a $12.3 billion water resources bill. Another Republican Senate hopeful, U.S. Rep. Paul Broun, figuring the bill would pass easily, stayed in Georgia to drum up votes, as did U.S. Rep. Hank Johnson, a DeKalb County Democrat facing a tough primary.

The 412-4 vote on a House-Senate conference report sends the bill to the Senate, where it is expected to pass soon. Once President Barack Obama signs the Water Resources Reform and Development Act, it clears the way for the Army Corps of Engineers to give the final sign-off to the $706 million deepening project — Georgia’s top economic development priority.

Republican U.S. Sen. Johnny Isakson of Georgia, during a Monday gathering of waterworks engineers and public officials in Marietta, said the Senate will likely pass the legislation unanimously. But a final vote may not come until early next month, he said; the Senate isn’t in session next week.

Construction will start with the $266 million Georgia taxpayers already have set aside, with the federal government’s share expected in the coming years. The water bill lists the full price at $706 million, well above the Army Corps’ 2012 estimate of $652 million.

Georgia business and political leaders expected a chunk of money in this year’s budget, but Obama administration officials insisted that Congress had to act first to pass this water bill, authorizing the project at its increased cost.

The vote came at an inopportune time for Georgia’s House members as they had their primary election Tuesday. Kingston said the unexpected quick trip to Washington didn’t bother him.

“You know, I just really want to get that thing done, so it’s certainly worth it,” he said Monday. “We’ve worked so hard on this thing for so long, to have an opportunity to get it to the floor really at any time, it’s really worth it.”

Before heading to Washington, Gingrey said he was keen to make the vote.

“I can’t miss the WRRDA bill, that’s too important for the state, and I’m still a member of the House of Representatives,” Gingrey said. “I wanted to fill that commitment.”

But Broun, who had voted for the water bill before and knew it would pass with ease, remained in Georgia for last-minute politicking.

“Dr. Broun believes it is important that he continue talking with Georgians about saving America from out-of-control government until the polls close,” spokeswoman Christine Hardman said.

The House bucked conservative concerns with the bill, including from Heritage Action for America. In a message urging House members to vote against the bill, Heritage wrote “it hikes spending while doing little to reduce bureaucracy and limit the role of the federal government.”

House aides pointed out that the bill authorizes $12.3 billion in new spending — including on Savannah — while clearing out $18 billion in old projects, for a net savings. It is the first time a water resources bill has been passed in the post-earmark era, as congressional leaders established a new process for picking projects.

House Speaker John Boehner at a news conference in Washington called it “a significant policy achievement.”

“It demonstrates the kind of progress that we can make when Democrats will work together with us to deal with the American people’s priorities,” Boehner said.