Congress reconvenes this week after a monthlong summer recess and begins what likely will be a final push toward overhauling prescription drug prices, but lack of consensus on the underlying policy and the intensifying 2020 presidential campaign will complicate efforts to advance a bill to President Donald Trump’s desk.

House Speaker Nancy Pelosi, D-Calif., is finalizing long-awaited legislation centering on price negotiation for drugs that lack competition, and she could introduce legislation as soon as this week. But the secretive process – even to most members of the Democratic Caucus – is causing frustration. Progressive lawmakers say the speaker’s plan may not go far enough on calling for government negotiation with manufacturers over prices.

Also in the House, the bipartisan leadership of the Ways and Means and Energy and Commerce committees are trying to work out details of a separate bill, which could see committee votes in the coming weeks. That effort focuses on the Medicare Part D prescription drug benefit, including creating an out-of-pocket cap for beneficiaries. Other provisions, such as cracking down on surprise medical bills, could be attached, too.

While the House committees’ effort may be running in parallel with Pelosi’s legislation, it’s not clear if the two are coordinated.

Overshadowing any drug-pricing legislation – as well as efforts to strike bipartisan agreements on trade, guns and spending issues – is the potential of a House-led impeachment investigation of Trump. Democrats on the Judiciary Committee are scheduled to vote this week to step up their inquiry as more rank-and-file Democrats are now calling for a formal impeachment investigation.

It’s challenging to see Trump and Pelosi negotiating policy differences on prescription drugs at the same time the speaker is ramping up an impeachment inquiry against the president. There’s also some sentiment among House Democrats not to give Trump a policy victory on drug prices that he would use in his 2020 re-election, especially if that bill falls short of progressive demands, such as government price negotiation over all drugs.

The Senate is further along in developing drug pricing legislation. Both the HELP Committee and Finance Committee earlier this summer approved separate measures addressing prescription costs.

Drug industry critic and Finance Chairman Charles Grassley, R-Iowa, pressured committee Republicans to back his effort, and he’s expected to step up calls on Majority Leader Mitch McConnell, R-Ky., to bring legislation to the Senate floor.

But nine Republicans voted against Grassley’s bill in committee, underscoring the deep divide among GOP senators over the chairman’s approach, which includes creating inflationary caps on price increases. While some senators pine for the old-school approach of bringing up legislation and allowing the Senate to work its will, McConnell has said he’s not scheduling votes on a bill that divides Republicans and unites Democrats.

With Congress reconvening, there will be a lot of noise and fury in the coming weeks over drug pricing legislation as advocates try to advance an overhaul. Trump could corner Republican lawmakers by endorsing a bill backed by Democrats, or legislative paralysis could continue as escalating partisanship grips Washington ahead of the 2020 elections.