Sen. Kay HaganKay Ruthven Hagan2020 Dems compete for top campaign operatives Senate GOP rejects Trump’s call to go big on gun legislation Politics is purple in North Carolina MORE (D) has expanded her lead to 7 points in the North Carolina Senate race, a crucial battleground, according to a new poll from Democratic firm Public Policy Polling.

Hagan leads North Carolina House Speaker Thom TillisThomas (Thom) Roland TillisSenate Gang of Four to meet next week on immigration Live coverage: High drama as hardline immigration bill fails, compromise vote delayed Senate moving ahead with border bill, despite Trump MORE (R) 41 percent to 34 percent with Libertarian candidate Sean Haugh pulling 8 percent support, according to the automated poll from the North Carolina-based firm.

Tillis has been stuck in session with the state Legislature, as Republican infighting has delayed the end of the legislative calendar and drawn negative headlines across the state. That could be playing a part in Hagan's growing lead. She was up 2 points in PPP's May survey and 5 points in June.

Hagan also has a big cash advantage in the race, with $8.7 million in the bank at the end of June to Tillis's $1.6 million. She's using that edge to buy up TV early while rates are still relatively low: Her campaign announced Tuesday that it had reserved $4.4 million in fall airtime.

The poll shows that 57 percent of voters disapprove of the GOP-controlled Legislature while 19 percent approve, a sign the association is dragging on Tillis.

Neither lawmaker is popular, however, explaining Haugh's strong pull in the race.

Hagan remains underwater, with a 40 percent approval rating and 50 percent of voters disapproving, while Tillis is in even worse shape, with a 24 percent approval rating and 47 percent disapproving. Third-party candidates' numbers often collapse on Election Day, and with Haugh removed, Hagan's lead shrinks to 42 percent to 39 percent, an indication that it is still a very competitive race.

Partisan polls should always be taken with a grain of salt, and automated polls are less reliable than live-caller surveys. But this is the latest sign that Hagan has opened a slight but steady lead over Tillis as they head into the fall campaign.

The automated poll of 1,062 North Carolina voters, with a 20 percent Internet sample to make up for cellphone-only users, was conducted July 17–20 and has a margin of error of plus or minus 3 percentage points.

This post was updated at 2:50 p.m.