US Senate Minority Leader Chuck Schumer, Democrat of New York, and House Democratic Leader Nancy Pelosi, speak about the Omnibus budget deal during a press conference at the US Capitol in Washington, DC, March 22, 2018.

The nonpartisan political newsletter, which tracks congressional, presidential and gubernatorial elections, made changes in 17 House races over the past week — all in Democrats’ favor.

Crystal Ball's managing editor noted that it was “the first time this cycle we’ve gone beyond 50-50 odds on a House turnover.”

An analysis by Sabato’s Crystal Ball , a service of the University of Virginia's Center for Politics, published on Tuesday shows the House tilting past 50-50 odds in favor of the Democrats taking it back. The party needs to flip 23 seats this fall in order to regain the majority they haven't held since the first half of President Barack Obama 's first term.

For the first time this cycle, a leading elections forecaster has given Democrats a greater than 50 percent chance to reclaim the House of Representatives in the 2018 midterms.

With under 100 days to go until the November elections, eight races labeled “Leans Republican” were shifted to the “Toss-Up” category, including a special election in Ohio on Aug. 7.

The changes raise the total number of toss-up elections to 36. Thirty-four of those competitive races are for seats currently held by Republicans, versus just two from Democrats.

Other pollsters and analysts have already signaled that Democrats have an edge heading into the midterms. Real Clear Politics’ generic ballot, which averages leading polls, gives Democrats a seven-point lead over the GOP. Forecasting and data site FiveThirtyEight estimates that Democrats have a higher chance than Republicans, 48 percent to 41 percent.

The shift toward the minority party follows a week of intensely negative press for President Donald Trump, whose performance during a press conference alongside Russian leader Vladimir Putin in Helsinki, Finland, garnered bipartisan condemnation.

The president’s approval rating is still largely stuck in the low 40s, which analysts say is a red flag that has plagued similarly situated presidents in past midterms. The House generic ballot, which has generally shown a Democratic lead of between six to eight points, is currently at the higher end of the range right now.

A poll by The Wall Street Journal and NBC News that was published Sunday showed Trump’s favorables edging slightly higher in the wake of the summit with Putin, helped almost entirely by high levels of support among Republicans. Eighty-eight percent of members of the president’s party approve of the job he’s doing, according to that poll.

In Congress, however, Sabato’s Crystal Ball shows a less steady base of support for Republicans. A high number of open seats in this election cycle provides Democrats with more opportunities to take back seats than the GOP, since Republicans are defending 41 seats without an incumbent, while Democrats are defending only 22 seats.

The analysts also note that Republican incumbents in 56 districts were badly outfunded by their Democratic challengers in the second quarter. It’s a potentially ominous sign for the GOP, considering incumbents are generally expected to be able to handily outraise their opponents.