In March 2015, we have a 2016 race for Maine’s 2nd Congressional District: On Tuesday, Democrat Emily Cain filed for a rematch against U.S. Rep. Bruce Poliquin, the Republican who beat her in November.

Much was made about her early announcement. In a statement, Poliquin’s political consultant accused Cain of “playing politics” while the congressman works in Washington.

Indeed, Cain declared early — for a challenger. Her announcement is the soonest of any non-incumbent, primary-winning candidate in any U.S. House of Representatives race in Maine since at least 1998, the earliest date that digital records are available through the Federal Election Commission. Most Maine challengers declare in the first half of the election year.

But for an incumbent, this is normal. Cain’s decision came a month after Poliquin declared his re-election candidacy. U.S. Rep. Chellie Pingree, a Democrat from the 1st District, said in December that she’d run for re-election in 2016, just after winning her fourth term.

Earlier filings are common in races expected to be close: Ahead of the open-seat 1st District race in 2008, Pingree filed in late March 2007, then won by 10 percentage points, as close a race as she has had since. The 2nd District seat was open in 2002, and Republican Kevin Raye filed in June 2007, while Democrat Mike Michaud filed that July. They won the primaries, and Michaud won narrowly.

Why file early? To paraphrase my colleague Steve Mistler: Fundraising!

After Cain’s announcement, she sent an email blast seeking donations, and Poliquin later asked for money on Facebook. Both parties have prioritized their 2016 race, and it’ll be expensive.

So, is Cain “playing politics” with her announcement? Of course. But Poliquin was already running and is also fundraising. So he’s “playing politics” too.

But we should expect that. After all, they are politicians.