RICHMOND — Virginia Democrats have raised historic amounts of money in the weeks leading to the Nov. 5 election that will determine control of the General Assembly, using infusions from national groups to far outstrip Republican totals.

A surge of cash in September brought Democrats to a total of $31.8 million raised so far this year, more than double the $13.7 million Democratic candidates raised in 2015, the last time all 140 seats in the legislature were on the ballot, according to an analysis by the nonpartisan Virginia Public Access Project.

Republican totals are up modestly, to $21 million from $17.7 million in 2015.

The September surge added to a lead that Democrats built up over the summer. Seven of the top 10 fundraisers are Democrats in both House of Delegates and state Senate races, according to a VPAP tabulation of campaign finance reports filed by midnight Tuesday. Those reports, covering the month of September, are the final full disclosures before Election Day.

“Winter is coming for Virginia Republicans,” Democratic Party of Virginia spokesman Jake Rubenstein said. “Absolute domination across the board. Excited to see how the Republicans spin their lack of energy, resources and message.”

Republicans argued that Democrats had inflated their totals by some $2.9 million by moving funds between candidates and party committees, leading to cases of double-counting.

"Our Republican team is well positioned for the final sprint to November, and unlike Democrats, we didn't need to resort to chicanery to inflate our numbers," said Garren Shipley, spokesman for House Republican leadership.

Republicans also noted that $2.24 million of the cash Democrats raised in September came from 15 donors, including Emily’s List, the national group for female candidates, which contributed $711,000 during the month, and Charlottesville power couple Michael Bills and Sonjia Smith, who together gave $250,000, according to a GOP analysis of state filings.

However, GOP candidates also are getting major infusions from national sources. The Republican State Leadership Committee, based in Washington, was the top overall donor for GOP candidates in September, giving more than $2.4 million.

Resources have gushed into Virginia as the only state in the country where this year’s elections will determine the legislature’s balance of power. Republicans are nurturing thin margins of 51-48 in the House and 20-19 in the Senate, with one vacancy in each chamber. With Democratic Gov. Ralph Northam in the Executive Mansion, a Democratic sweep of the legislature would give the party its first consolidated hold on power in a generation.

The races attracting the most money are in suburban swing districts in Northern Virginia, the Richmond area and Hampton Roads. Democrats believe they can unseat Republicans in those districts with issues such as gun control and health-care reform, piggybacked on the disapproval of the Trump administration that helped power big gains for the party in 2017.

The top fundraiser for the period is Democrat Debra Rodman, a delegate running for a Senate seat outside Richmond, who pulled in more than $1 million in cash and in-kind contributions. Her opponent, Republican incumbent Sen. Siobhan Dunnavant, raised less than half that amount, $421,000. Rodman also has almost twice as much cash on hand — $399,000 to Dunnavant’s $220,000.

Several closely contested seats in Northern Virginia are among the most expensive statewide.

Del. Tim Hugo — the last Republican remaining in the blue D.C. suburbs — raised $242,500 in September to defend his seat, with $314,000 remaining in the bank. Democratic challenger Dan Helmer raised slightly more — $281,000 — but has less cash on hand, at $218,000.

Republicans are also targeting several freshman Democrats in Northern Virginia who flipped red House seats blue in 2017, leading to big fundraising totals. Del. Hala Ayala of Prince William County raised $533,000 in September, with the bulk of it coming from Emily’s List and Democratic Party committees as she holds off a challenge from the man she beat two years ago, Richard Anderson. He raised less than a tenth of that amount, at $43,300.

Both sides have racked up big totals in nearby Loudoun County, where Democratic Del. Wendy Gooditis posted the biggest September haul of any House candidate, at $580,000. She faces a challenge from the Republican she beat two years ago, Randy Minchew, who raised $287,000.

In the exurbs of Northern Virginia, an open House seat previously held by Republicans is shaping up as a key race. Democrat Joshua Cole raised nearly $238,000 in September and ended the month with more than $286,000 on hand. That doubled the fundraising of his Republican opponent, Paul Milde, who raised just under $107,000 in September and finished with $21,000 on hand.

The most expensive House race is shaping up to be the battle for the Colonial Heights seat of Speaker Kirk Cox, a Republican who raised nearly $303,000 in September and has $362,000 on hand. His challenger, Democrat Sheila Bynum-Coleman, raised $568,700 and has about $473,500 on hand.

Federal judges redrew the district earlier this year after ruling that Virginia’s House map had been racially gerrymandered. The new configuration left Cox and five other Republicans in districts that now lean Democratic. National donors have flooded Bynum-Coleman with cash: Emily’s List and Everytown for Gun Safety each gave $125,000 in September alone.

That forces Republicans to spend money on Cox’s formerly safe seat, limiting his ability to spread support to Republicans around the state.

Still, Republicans are throwing money at several suburban House and Senate races in Richmond and Hampton Roads that are key battlegrounds for control of the legislature.

In an open House seat in an affluent section of Henrico County, Republican Mary Margaret Kastelberg raised $309,000 in September and has a war chest of $136,500. Her Democratic opponent, Rodney Willett, raised $244,000 and has just over $121,000 on hand. Willett is trying to hold onto a seat that Democrats won in the wave of 2017; the incumbent, Rodman, is running for Senate.

A Senate seat in Richmond’s West End is another crucial race, with Democratic challenger Ghazala Hashmi raising more than $645,000 in September to take on incumbent Republican Glen Sturtevant, who raised $289,000 for the month. Hashmi has spent a lot, though, and her $251,000 on hand is just slightly more than Sturtevant’s $196,000.

In Virginia Beach, Republican Sen. Bill DeSteph raised about $55,600 in September to defend his seat against Democrat Missy Cotter Smasal, who took in 10 times as much, almost $575,000. She also has the edge in cash on hand, at $368,000 to his $245,000.

The other big Senate battle in Hampton Roads is for the Norfolk and Virginia Beach district once held by Republican Frank Wagner, who retired. Democratic candidate Cheryl Turpin, who was a freshman delegate, raised almost $675,000 last month to contend for the seat, which has become more blue over the years. Republican Jen Kiggans raised about half that, at just over $330,000. She has $167,500 on hand to Turpin’s $251,000.

Democrats are also making big pushes in races that seem like a stretch, given past voting patterns. In a Senate district outside Fredericksburg that’s largely rural and red but becoming more suburban, Democratic challenger Amy Laufer raised more than $344,000 in September and finished the month with $134,700 on hand. Republican incumbent Sen. Bryce Reeves — who vied for his party’s nomination for lieutenant governor in 2017 — raised $65,600 for the month and has $248,000 on hand.

And in a red House district that stretches from the Eastern Shore to parts of Norfolk and Virginia Beach, Democrat Phil Hernandez raised $258,000 in September and ended the month with almost $364,000 in reserve. Incumbent Republican Del. Rob Bloxom raised just over $95,000 and has $120,300 on hand.

The Tuesday campaign finance reports also showed the degree to which Northam’s fundraising has been weakened by a blackface scandal that enveloped him earlier this year. His political action committee raised just over $430,000 in the period from July 1 to Sept. 30; that compares with $1.4 million during the same time period in 2015 for former governor Terry McAuliffe (D) and $855,000 during the same portion of 2011 for former governor Bob McDonnell (R), according to an analysis by VPAP.