Democrats are leading Republicans by 17 points on a generic ballot, according to a new USC Dornsife/Los Angeles Times poll.
The survey, conducted Oct. 21-27, found that 57 percent of likely voters said they plan to cast their ballots for Democrats in the Nov. 6 midterm elections, compared with 40 percent who plan to vote for Republican candidates.
The data released on Monday show a 4-point gain for Democrats following an LA Times poll the previous week that found the party leading by 13 points.
The poll also found higher levels of enthusiasm among Democrats, with 52 percent saying they will vote in the midterms, while only 42 percent of Republicans said the same.
The survey was conducted before, during and after several pipe bombs were mailed to prominent Democrats. The final day of the poll was Saturday, when 11 people were killed during a shooting at a Pittsburgh synagogue.
Democrats are showing signs of confidence about taking back the House, but gaining seats in the Senate is proving more challenging. Data analysis site FiveThirtyEight says Democrats have an 86.6 percent change of winning control of the House, and an 18 percent chance of taking the Senate.
Other recent polls have shown Democrats leading the GOP by single digits on the generic ballot.
Democrats need to pick up 23 seats in the House to win the majority.
The USC Dornsife/Los Angeles Times poll surveyed 3,922 adults and had a margin of error of 2 percentage points.