WASHINGTON, D.C. — Congress returns to Washington this week amid mounting pressure from Democrats and the public to enact new gun restrictions, but lawmakers from both parties say meaningful action hangs solely on President Donald Trump.

Since lawmakers were last in session Aug. 2, three mass shootings have killed 38 people and injured many more.

The White House is expected to release gun policy proposals that Trump supports, possibly this week. But few gun safety advocates or Democrats are optimistic that the proposals will be as expansive as they want.

Returning lawmakers will also face a quick deadline to fund the government again, or risk another shutdown.

And the White House needs to pick up the pace on negotiations with Congress over a revised NAFTA trade agreement if Trump's top legislative priority, now called the United States-Mexico-Canada trade agreement, is to become law this year. All the while, some House Democrats will be clamoring to get impeachment proceedings against Trump underway.

The White House gun proposal comes at the urging of Senate Majority Leader Mitch McConnell (R-Ky.), who is trying to balance growing public support for increased background checks with a slate of Republican senators who are skeptical of angering the powerful gun lobby.

McConnell said no legislation will get a vote on the Senate floor without approval from Trump, whose popularity in Republican-leaning states would give political cover to Republican senators to vote in favor.

Even the most ardent gun control supporters acknowledge only Trump can move the needle in Congress.

"If after all this and what he has said, if President Trump fails to take a clear position and lead, I think there will be very widespread disappointment and anger," said Sen. Chris Coons (D-Del.).

Sen. Roy Blunt (R-Mo.), a member of the GOP leadership, said Trump needs to "set some guidelines" for what he would support. "The president needs to step up here," Blunt said Sunday on NBC's "Meet the Press."

But he warned against doing nothing at all. "We take this silly, 'If we don't get everything, we don't do anything' (approach) and fail to do the things we could do," he said.

Trump has been unclear on where he stands. After back-to-back mass shootings last month in Texas and Ohio, the president said he was open to enhanced background checks, but then later seemed to back track and echo the position of the powerful National Rifle Assn.

One possible outcome is that the White House releases a proposal that Democrats view as inadequate, a move that could force Democrats to choose between supporting weak reforms or rejecting it for the status quo.

While the gun debate could linger, Congress faces a more pressing deadline to approve spending bills to avoid another government shutdown on Oct. 1.

Neither party wants another shutdown. House Democrats are eyeing a stopgap measure to fund the government through Nov. 22, just before lawmakers leave town for Thanksgiving.

House Democrats have enacted 10 of the 12 required spending bills, but the Senate has done none. While Senate Republicans plan to work on those bills this week, there's little time to sort out the differences between the House and Senate bills. Senate Republicans are likely to rebuff the House stopgap plan, but it is unclear whether they would block its passage.

The House is scheduled to be in Washington for only 10 more weeks this year, meaning that any legislation Democrats hope to pass — such as prescription drug policy or a new trade agreement — must be acted upon soon.

Negotiations between the Trump administration and Congress on the new USMCA trade agreement are expected to pick up. House Democrats have several outstanding concerns about the language on prescription drugs, climate change and enforcing labor standards in Mexico.

In the House, Speaker Nancy Pelosi (D-San Francisco) will contend with brewing support among her rank-and-file caucus members for impeaching the president.

More than half of the 235 Democrats support starting an impeachment inquiry, a symbolic milestone hit over the August recess. House Judiciary Chairman Jerrold Nadler (D-N.Y.) said recently that the House is already in effect conducting "formal impeachment proceedings."

Pelosi has long resisted starting a formal inquiry without broad public support for impeachment and overwhelming evidence of wrongdoing. But other Democrats have grown frustrated that the House has not moved forward.

"There is a very solid majority of the caucus now on the right side of history," said said Rep. Jared Huffman (D-Calif.), a prominent advocate of an impeachment inquiry. "The pressure to really do more and to do it faster is only going to grow."

Los Angeles Times