Lawmakers are back onCapitol Hill on Monday after an extended summer recess with a short window to tackle major legislative priorities before the 2020 presidential campaign takes center stage.

Republicans and Democrats in the Senate and House need to approve spending bills to avoid another government shutdown. They also hope to make progress on policy debates that have been languishing for months: the White House is pushing Congress to ratify a new trade deal with Mexico and Canada, and leaders want to show voters they are serious about proposals to lower health care costs.

A string of mass shootings in August that left more than 50 dead also added a contentious debate about gun control measures to the fall agenda.

But the ongoing battle royal between President Trump and House Democrats about investigations into his administration and increasing calls for his impeachment make bipartisan cooperation a tall order in a divided Congress.

Here's an overview of what Congress plans to address this fall:

Guns

Senate Majority Leader Mitch McConnell, R-Ky., a longtime supporter of Second Amendment rights, ignored the bill expanding federal background checks that the Democrat-controlled House passed in February. But after several late summer mass shootings, President Trump publicly said he wanted Congress to act in early August and McConnell said the Senate would debate a range of issues after the summer break. Democrats spent weeks urging McConnell to call the Senate back, but he emphasized that he would only advance gun legislation that the president backed.

In an interview last week, McConnell reiterated that he was waiting for the president to clarify which proposals he would get behind in September before allowing votes on the Senate floor.

The White House has been talking with Sen. Pat Toomey, R-Pa., and Sen. Joe Manchin, D-W.Va. — the two senators pushing a background check bill — about their bill. There are also bipartisan efforts to pass legislation that gives grants to states to implement red flag laws — measures that allow law enforcement to temporarily remove guns from those who could pose a risk to themselves or others.

But the president has reversed himself in the weeks following the shootings in Texas and Ohio, and without his express support the debate is stalled. The leadership of the National Rifle Association has had a direct line to President Trump and is opposed to the current proposals circulating on the Hill. Republicans have largely stayed silent on what they are ready to support. Without cover from Trump, few lawmakers are eager to get on the wrong side of the NRA, which has been a powerful force in national election cycles.

House Democrats aren't waiting on a deal with the White House. The House Judiciary Committee is expected to advance three bills this week — one giving incentives to states for red flag laws, one banning high capacity magazines for firearms, and one banning firearm sales to individuals with misdemeanor hate crime convictions. The committee is also holding a hearing later in the month on legislation banning assault weapons. It's likely the full House will vote on those proposals this fall in an effort to pressure the Senate to act.

Spending

President Trump signed a two-year budget bill earlier this summer setting the top-line numbers for defense and domestic programs. That deal removes a major hurdle for negotiators on the appropriations committees who are allocating specific agency budgets. But both chambers still need to approve the spending bills for federal agencies. The House has already passed the bulk of these, but the Senate still has to move its own versions.

With the deadline to avoid another shutdown looming on Sept. 30, House Majority Leader Steny Hoyer, D-Md., announced the House would vote in mid-September on a stopgap funding bill to keep agencies funded through sometime later this fall as the two chambers negotiate final spending bills.

"As we wait for them to complete their work so that we can begin conference negotiations, a continuing resolution will be necessary to prevent another government shutdown like the one we experienced earlier this year, which harmed thousands of American families," Hoyer said in a letter to House Democrats last week.

Senate Republicans have not said whether they support the House's bill, or whether they will move a separate measure. Any effort to tack on money for a border wall or other GOP priorities to a spending bill could potentially trigger another shutdown.

Prescription drug prices

Republicans and Democrats both say one of voters' chief concerns is the high cost of prescription drugs. But their policy proposals on how to bring costs down are significantly far apart. Democrats want to impose government regulations, while GOP lawmakers are reluctant to interfere in free markets. President Trump has vowed that lowering drug costs is a key theme heading into his 2020 reelection bid.

The Trump administration has taken some executive action to impose new rules for drug companies, but they have had little impact so far because they are still going through the rule-making process or mired in legal challenges.

Efforts to tackle the issue have faltered for years, with the powerful drug lobby spending millions to oppose major reforms on Capitol Hill.

Senate Finance Committee Chairman Chuck Grassley, R-Iowa, led the effort to move a bipartisan bill through his committee in July. But most Republicans on the panel opposed that plan. It included price controls on the pharmaceutical industry, limiting their ability to raise drug prices faster than the rate of inflation.

House Democrats are planning to unveil their own proposal later this month that will focus on Medicare negotiating drug prices in an approach designed to lower costs for consumers in both government and private health care systems.

It's likely the issue will be a central one in congressional races next fall. It's the focus of a political campaign commercial in a special election for a House seat in North Carolina, where the Democratic candidate is accusing his GOP opponent of siding with wealthy drug company CEOs over cancer patients.

Trade

The president is aggressively pushing Congress to ratify the United States-Mexico-Canada Agreement known as USMCA this fall. A trade war with China ratcheted up over the summer, and lawmakers representing farmers and manufacturers impacted by new tariffs are eager to finalize the deal they hope will significantly increase U.S. exports and boost job creation.

But House Speaker Nancy Pelosi insists that the deal needs stronger enforcement provisions. She has specifically called for those related to labor standards, prescription drug prices and environmental protections.

The president's trade representative, Robert Lighthizer, has been in regular contact with Pelosi for months. A working group of House Democrats tapped in June by the speaker has been working to get the administration to make changes to the agreement. Pelosi has also talked with Canadian Prime Minister Justin Trudeau about her concerns.

McConnell continues to press Pelosi to move forward with the deal, saying there is overwhelming bipartisan support for it in the Senate. The formal agreement hasn't been transmitted to Congress, and if it slips into 2020 it is far less likely that it will get approved. Democrats will be reluctant to give the president a win on one of his key 2016 campaign promises just months before voters decide whether he deserves a second term.

Investigations and impeachment

Multiple House committees continue to investigate President Trump's finances, businesses and administration policies. Despite a flurry of subpoenas to top White House officials and former campaign aides, the Democrats' efforts to obtain documents have been largely stonewalled and few witnesses have agreed to appear.

Even during the summer recess both the House judiciary and oversight panels continued to pile on more issues they are examining — including the vice president's decision to stay at a Trump-owned resort during an official visit to Ireland.

Proponents of impeaching the president hoped to use the summer recess to drum up pressure on those Democrats who haven't publicly backed moving ahead. One marker impeachment advocates can hold up is the fact that a majority of House Democrats are now publicly calling for an impeachment inquiry.

But recent public opinion polls indicate that the majority of Americans oppose impeachment. Pelosi, who will ultimately determine whether the House proceeds, is against any formal impeachment effort until the strong case is built and the public is on board. She recently restated her view to House Democrats on a conference call, emphasizing that the public support isn't there yet.

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