Incumbent senators are sitting on a combined total of more than $77 million as they stockpile campaign cash ahead of next year’s elections.

Fourteen incumbent senators pulled in more than $1 million in the last quarter, and eleven now have at least $3 million in the bank, according to forms filed with the Federal Election Commission this week and analyzed by The Hill.

The fundraising hauls are just the beginning of what is likely to be a pitched battle for control of the Senate. Republicans are defending 22 seats next year, while Democrats have 12 seats on the table.

Republicans hold 53 seats in the Senate, meaning Democrats would have to pick up a net of at least three seats and the White House to win back the majority, or four seats to hold control regardless of who wins the presidency.

The fundraising results offer the earliest hints at the contours of next year’s battlefield.

Both McSally and Gardner have drawn challengers who have already posted impressive fundraising numbers of their own.

In Arizona, former astronaut Mark Kelly (D) pulled in more than $4.1 million and has $3.2 million in the bank. In Colorado, former state Sen. Mike Johnston (D) raised $1.8 million in his first weeks on the trail, though he faces an increasingly crowded Democratic primary field.

“People in potentially competitive races really have to use every day to move the ball forward for their race, and that means fundraising, press, politics,” said Martha McKenna, a Democratic strategist and former senior operative at the Democratic Senatorial Campaign Committee. “If you’re headed for a tough 2020, taking fundraising very seriously is the top of your list.”

Political observers use the early numbers to gauge just how seriously a sitting senator takes his or her reelection bid.

A strong quarter is unlikely to dissuade a challenger from running, though a weak quarter can be an early red flag that a senator is taking it easy during a crucial stretch.

“If you’re an incumbent and you have a bad quarter it shows how unprepared you are for what’s coming your way. This should be a quarter where you can knock it out of the park,” said Rob Jesmer, a former executive director of the National Republican Senatorial Committee and a top adviser to Cornyn. “You realize right away who has a good operation and who doesn’t.”

All four would likely skate to reelection; Enzi, Risch and Inhofe represent safely red states, though none of the three Republicans have formally said they will seek another term.

Inhofe’s campaign said the Oklahoma Republican had actually raised more this quarter, $334,000, than he had at this point six years ago.

Reed’s Rhode Island is deeply Democratic, and he will attend a campaign fundraiser with Walt Disney Co. executives this week.

The fifth senator lagging on the fundraising circuit is Sen. Cindy Hyde-Smith (R-Miss.), who has just $217,000 in the bank. She has just begun to rebuild her campaign account after winning a special election to fill the final two years of her predecessor’s term.

Some senators who may face tough races started off the cycle at a slower fundraising clip.

Sen. David Perdue (R-Ga.) raised $1.8 million in the first quarter of the year, and ended with more than $3.3 million in the bank. Perdue, who gave his own campaign $3.9 million six years ago, faces the prospect of a challenge from former gubernatorial candidate Stacey Abrams (D), who has built her own network of national donors.

Perdue’s situation is like many of his colleagues, on both sides of the aisle: His most prominent potential challenger has not yet made a decision about whether to jump in the race, underscoring just how long there is to go before voters have their say.

Prominent candidates have not made final decisions in states like Alabama, Michigan, Texas, Kentucky, Iowa or North Carolina.

But, the Democratic strategist McKenna said, now is the time for candidates to begin sucking up cash. The battle for the White House has already begun in earnest, offering a shiny and enticing distraction to donors who might otherwise pay attention to down-ballot contests.

“This is the window, because the presidential’s going to start sucking up all the attention,” McKenna said.