Priorities USA, a top Democratic super PAC, cautioned Democrats Tuesday to stay focused on economic messaging in the lead up to the midterms because diverting attention elsewhere could cost them the election.

Spending time on unorganized criticisms of President Trump or other policy issues, the Democratic group warned in a memo, could jeopardize Democrats' chances of success in a rich political environment that currently skews in their favor.

Polling conducted by the super PAC shows Trump’s approval rating ticked up to 44 percent in the first week of February from 40 percent approval in November. And Democrats’ advantage on the generic ballot fell, narrowing the the gap to 46 percent preferring Democrats to 42 percent for Republicans, according to the survey.

The group doesn’t mince words, blaming the Democrats' shrinking lead on their inability to focus the public on Trump’s economic policies, taxes and healthcare.

“The extent of Democratic gains will be blunted if Democrats do not reengage more aggressively in speaking to the economic and health care priorities of voters,” the memo states. "There’s no question that Trump benefits when a critique of his tax and healthcare policies is not front and center – especially when voters are hearing Trump’s side of the story on the economy."

Though Democrats maintain the lead, the group says, the party “must reassert control over the economic narrative if they are going to maximize electoral success” across the board.

Priorities USA doesn’t tell Democrats to steer clear of immigration or social issues, but to continually be loud on taxes and healthcare. Democrats can’t be “sidetracked and distracted by Trump’s latest tweets,” the memo said.

The noise coming from Democrats last week centered around immigration, as party leaders in the House tried to pressure Republicans for a commitment on legislation to help so-called Dreamers. Indeed, Minority Leader Nancy Pelosi’s record-long speech on the House floor in defense of Dreamers drew the ire of the centrists in her caucus. Some said it split Democrats, and wouldn’t help those in red states who are trying to win over waffling Trump voters or undecideds.

The need to center their national messaging around the economy isn’t lost on a number of Democrats. Rep. Cheri Bustos, who represents an Illinois district Trump won, issued a report in January arguing Democrats need to win rural areas to gain the majority. To do that, Democrats need to improve the party brand by focusing on the economy.

“In 2018 we may be lucky enough to pick up enough seats just because the president’s popularity is going down further and further, but that’s not a long term strategy,” Bustos told the Washington Examiner in late January. “A long-term strategy is to make sure that people don’t identify everything through a partisan lens.”

“The issues that bring people together, they all revolve around the economy,” she added.

Despite delivering some bad news for Democrats, Priorities USA provided the party with some uplifting data points. Only 35 percent of undecided voters approve of Trump, compared to 50 percent who disapprove. Undecideds aren’t typically reliable voters in a midterm but Democrats also lead Republicans on voter enthusiasm ten months out.

The memo surveyed 1,001 voters during the first week of February. It was compiled in partnership with Global Strategy Group and GarinHartYang Research Group, two top Democratic political consulting firms.