Wall Street stocks dipped Tuesday after two positive session as investors digested the latest effort to try to jumpstart Washington stimulus talks amid caution ahead of the first presidential debate.

The Dow Jones Industrial Average shed 0.5 percent to 27,452.66.

The broad-based S&P 500 also dropped 0.5 percent to 3,335.47, while the tech-rich Nasdaq Composite Index lost 0.3 percent at 11,085.25.

Tonight’s debate in Ohio pits President Donald Trump against Democratic challenger Joe Biden and comes after US politics were rocked anew by revelations from a New York Times expose that said Trump paid no taxes for 10 of the last 15 years.

Biden is ahead in national polls and in several crucial swing states, but a debate win by Trump could shake up that dynamic.

Congressional Democrats on Monday unveiled a trimmed-down $2.2 trillion stimulus bill, a scale still well above the level supported by Senate Republicans.

On Tuesday, a top aide to Democratic House Speaker Nancy Pelosi said the lawmaker had spoken for the second day in a row with Treasury Secretary Steven Mnuchin, and the two agreed to continue negotiating, raising hopes the impasse could end.

Consumer confidence in the US jumped to 101.8 in September, The Conference Board reported on Tuesday, ending months of decline with a 15 point-plus gain from August despite no new federal stimulus.

A note from Schwab described markets as shrugging off the better consumer data, “with investors cautious ahead of tonight’s first presidential debate.”

Among individual companies, electric truck companies Nikola slid 7.4 percent as former chairman Trevor Milton faced accusations of sexual assault, another negative headline even though Milton has left the company.

Beyond Meat jumped 9.5 percent as it announced it is expanding its distribution partnership with Walmart to 2,400 stores in the US from 800 previously.