The elections have changed the political landscape and will affect the Mueller investigation, the border wall, the economy, healthcare, climate change and redistricting

What do midterms mean for … climate change, the economy and other issues?

Trump-Russia investigation

Democrats in the House of Representatives are likely to reopen an intelligence committee investigation into Russian interference in the 2016 election – and begin assisting the criminal inquiry on the same subject by the special counsel Robert Mueller.

Devin Nunes, the committee’s outgoing Republican chairman and a Trump ally, obstructed efforts by Democrats to investigate possible collusion with Russia by Trump’s campaign team, and closed the investigation with leads left unexplored.

Nunes also declined to share information with Mueller.

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But Adam Schiff, Nunes’s likely Democratic replacement, has promised to resume the committee’s inquiries and pursue new avenues such as the Trump Organization’s business links to Russia.

The extension of the Republican majority in the Senate, however, may embolden Trump to nominate a harder-line replacement for the attorney general, Jeff Sessions, fired the day after the election, in order to get rid of Mueller and shut down the special counsel’s investigation. If that happens, expect some Democrats to propose rehiring Mueller as an independent counsel to continue his investigation on behalf of the House. Jon Swaine

Immigration

Now that Democrats have the House, President Trump’s dream of a “big, beautiful wall” will be all the more elusive.

Trump accuses black reporter of asking 'such a racist question' and attacks CNN – live Read more

Before the midterms, the outgoing House speaker, Paul Ryan, promised there would be a “big fight” over the border wall immediately after the election. The Senate majority leader, Mitch McConnell, said this was still the plan on Wednesday morning, but Republicans now go into that fight against an emboldened Democratic party.

By 8 December, Congress must reach a deal on Department of Homeland Security funding, including the wall – a narrow window for Republicans to secure significant wall funding before Democrats take control of the House in January.

House Democrats have also said they will try to restore protections for Dreamers, undocumented immigrants who arrived in the US as children. Voters on both sides of the aisle have expressed broad support for creating a pathway to citizenship for this population and the Trump administration has used them as a bargaining chip since revoking their protections in 2017. Amanda Holpuch

The economy

Unless Trump gets re-elected in 2020, it now looks certain his massive tax bill will be his last. That $1.5tn giveaway, Trump’s largest congressional achievement, mainly benefited the very wealthy and corporations and has polled badly with voters, so badly that Republicans barely mentioned it in the run-up to the midterms. He has since promised another tax cut aimed at the middle class.

Now, with Democrats in control of the House, any legislation will be hard to pass.

There are areas of common ground – Trump counselor Kellyanne Conway has already mentioned infrastructure – but given the partisan divide in Washington, striking a deal is going to be difficult.

Facebook Twitter Pinterest Improvements to infrastructure, such as the Amtrak lines at Penn Station in New York, could be a potential area of bipartisan cooperation. Photograph: Kathy Willens/AP

The picture on trade also becomes more complex as the president’s powers are curtailed. Politicians in China, Europe, Canada, Mexico and elsewhere will all be watching to see how his defeat will affect the trade disputes he has fueled.

Trump can still use executive orders to force through change but the president’s chances of passing meaningful legislation were hobbled on Tuesday. Now he will be buffeted by the larger, outside forces that will decide the US’s economic forces – forces that are beyond his control. Dominic Rushe

Healthcare

Republican efforts to dismantle the Affordable Care Act (ACA) at a national level are almost guaranteed to halt now that the House is in the hands of the Democrats.

Democrats’ win of the House creates a dam that can block Trump's agenda | Gary Younge Read more

At the state level, Democratic governors-elect in Kansas, Maine and Wisconsin could expand ACA protections that Republican state leaders rejected. And in Idaho, Nebraska and Utah citizens voted to expand access to free or low-cost health coverage to the poor through Medicaid.

Before the election, Nancy Pelosi, who is expected to return to her former role as House speaker, said a legislative priority would be lowering pharmaceutical drug costs – an issue that could have bipartisan support.

And reproductive rights groups have called last night’s results a victory. Federal efforts to limit women’s reproductive rights will be challenged with Democrats in control of the House. And in Michigan, Kansas and New Mexico, the three governors-elect have a record for defending women’s reproductive rights. Amanda Holpuch

Climate change

Attempts to ramp up action to address climate change faltered, most notably in Washington state where voters rejected a proposal to implement a price on carbon pollution. The plan, which was vigorously opposed by oil and gas interests including BP, would have placed a $15 fee on each ton of CO 2 and potentially acted as a springboard for other states to do likewise.

Facebook Twitter Pinterest Voters in Washington rejected a carbon tax for the third time, raising questions about this approach to tackling climate change in the US. Photograph: Jeff Hunter/Getty Images

Washington state voters have now rejected carbon pricing on three separate occasions, raising doubts as to whether the concept, backed by many economists as the best way to drive down emissions and avoid disastrous climate change, will gain traction in the US.

Elsewhere, a ballot proposal to require that Arizona get half of its electricity from renewable sources like solar and wind was rejected by voters in the state. In Colorado, the fossil fuel industry spent $40m to successfully fend off an attempt to impose a half-mile buffer between drilling operations and people’s homes. In Florida, however, voters backed a measure to ban oil and gas drilling in state waters. Oliver Milman

Redistricting

Democrats picked up seven governor’s seats by early Wednesday.

The governor races are particularly important because of a once-in-a-decade redistricting process due to begin in 2021. States will be required to redraw congressional districts to make sure each one represents the same number of residents.

That’s where gerrymandering – the process where a party draws often oddly shaped districts to best maximize their voters – can occur.

State legislatures do the redrawing, but it is the state’s governor who has the ability to sign or veto the new congressional map in their state. That means a Democrat governor elected on Tuesday to a four-year term would have the power to prevent Republicans – who have become experts at gerrymandering, most notably in Pennsylvania – from redrawing districts in a way which would benefit them in upcoming elections to the House of Representatives.

Florida was seen as particularly important as the state is expected to gain two congressional seats after the 2020 census. That’s down to a long-term population shift away from the north-east and midwest towards states like Florida and Texas. Unfortunately for Democrats, Andrew Gillum lost on Tuesday. Adam Gabbatt