Republicans’ attempt to repeal the Affordable Care Act passed another major hurdle on Thursday afternoon after it was approved on a party-line vote by the House energy and commerce committee.

The committee’s backing for the bill followed an early morning vote by the House ways and means committee, the other congressional committee currently reviewing the draft legislation.

The American Health Care Act has been the subject of bipartisan controversy since it was unveiled by the House speaker, Paul Ryan, on Monday. Democrats have universally opposed the effort to repeal the healthcare law, often called Obamacare, while many conservative Republicans object that the draft legislation doesn’t do enough to dismantle it.

A glossary of key terms in US health care policy Co-pay

Out-of-pocket expenses ​for ​paid by patients for doctors’ visits, drugs or procedures. Deductible Amount a patient must pay out of pocket for prescriptions or healthcare before their insurance coverage kicks in. Healthcare exchanges The name for state insurance marketplaces created under the Affordable Care Act. Individuals shopping for health insurance can see what subsidies they may qualify for and sign up for a plan. ​But in some areas shoppers face a lack of options. ​ Individual mandate A penalty for people who don’t carry health insurance policies. ​As such it’s unpopular. But it’s also the linchpin to the Barack Obama health care law; w ​Without it, not enough healthy people would carry insurance to make a market. Medicaid A joint federal and state program that helps with medical costs for some people with limited income and resources. ​One of the largest payers for healthcare in the United States, with 70m enrollees. Spending accounted for 10% of the federal budget in 2015. Established by the Social Security Act, signed into law in 1965. ​ Medicare A federal health insurance program for people who are 65 or older, certain younger people with disabilities and others. ​The biggest public health care program by cost ($540bn in 2015, or 15% of the federal budget) with an enrollment of about 57m. Established by the Social Security Act, signed into law in 1965. ​ Premium If you need insurance, this is what it will cost you. The premium is a periodic payment for health or prescription drug coverage. Single-payer A pie-in-the-sky (for America) system in which a single payer, the government, would pay all health bills. Could that possibly work? The UK’s NHS is exhibit A. –Tom McCarthy

One prominent Republican critic, Senator Tom Cotton of Arkansas, tweeted on Thursday morning: “House health-care bill can’t pass Senate w/o major changes. To my friends in House: pause, start over. Get it right, don’t get it fast.”

Democrats also objected to the pace at which the AHCA was pushed through the committee process. In particular, they were upset that the Congressional Budget Office had not yet delivered its verdict on the costs of the scheme and its effects on insurance coverage. The CBO’s “score”, the best estimate of winners and losers from the proposed legislation, is expected on Monday.

However, Donald Trump and Ryan, the most senior Republican in Congress, have focused far more on recalcitrant Republicans than on any efforts to woo Democrats. Trump held a meeting on Wednesday with conservative activists opposed to the healthcare bill in an attempt to win them. The president will also have members of the Freedom Caucus, the conservative bloc among House Republicans, over to the White House for bowling next week in an attempt to persuade them.

Trump will also be holding events throughout the country to sell the legislation, including a rally scheduled for next week in Nashville, Tennessee. “Despite what you hear in the press, healthcare is coming along great. We are talking to many groups and it will end in a beautiful picture!” he tweeted on Thursday.

Meanwhile, Ryan held a televised news conference where he spent 25 minutes laying out his argument for the AHCA via a PowerPoint presentation. The House speaker said that many of the imperfections in the draft legislation were because of the tight focus of the reconciliation rule, a Senate procedure to avoid filibusters on legislation that deals exclusively with the budget.

The Wisconsin Republican insisted that much of the concern on the right stemmed from fellow conservatives not understanding that “this reconciliation rule is pretty tight”. He also warned Republicans opposed to the AHCA: “This is the closest we’ve been to repealing and replacing Obamacare and the closest we will get.”

Conservative critics were unconvinced. Congressman Justin Amash of Michigan tweeted shortly after the press conference: “‘Binary choice’ fallacy is a tool partisans on both sides use to quash policy debate and avoid difficult job of persuading and legislating.”

However, Republican supporters of AHCA are using other tools besides PowerPoint. The American Action Network, a conservative group connected with House leadership, will begin running television ads pushing 30 conservative skeptics of the bill to support it.

Why is healthcare so expensive in the USA? It’s the prices. That’s not a joke. Drugs, diagnostics, medical devices, doctor visits, hospital visits, procedures, scans, surgeries – “the United States spends more on health care than any of the other OECD countries spend, without providing more services than the other countries do ​, ​”, according to a widely cited 2003 paper on the topic entitled It’s the Prices, Stupid. Why are prices so high? In short, lack of a national system. The US system is employer-based, with most Americans – about 150 million non-elderly people – getting insurance through their employers, instead of straight from Washington. No national system means there is no single authority – no single payer – to go to bat on behalf of the consumer, although the big public healthcare programs, Medicare and Medicaid, do negotiate with providers on some costs. US healthcare providers can therefore get away with charging more, as can medical device manufacturers and drug makers. Doctors can order more tests, ambulances can charge more for transport and, on the other side, insurance companies can put up stronger resistance to paying claims, or charge more for coverage. The enormous inefficiency of the system is itself costly, as all sides have to spend money on analysts and lawyers and bookkeepers and anxiety medication. Why can’t market forces resolve the problem? Because it’s a highly irregular market, with highly localized supply and demand, instantly fluctuating demand (from no-need to need-now-at-any-price) and high barriers to entry for would-be suppliers of insurance, pharmaceuticals, or care itself. Tom McCarthy

The bill would eliminate the current healthcare law’s individual mandate, which requires Americans to have health insurance or pay a fine; cut the number of people insured under Medicaid; and allow insurance companies to charge the elderly up to five times more than the young. It would require insurers to cover so-called pre-existing conditions but would allow them to add a 30% surcharge to premiums if people go without insurance for too long.

Obamacare was the former president’s signature domestic policy achievement and enabled 20 million previously uninsured people to obtain health coverage, about half from an expansion of Medicaid that the new bill would end. It established subsidized state marketplaces for health insurance, which have struggled with rising monthly fees, set out what coverage insurers must offer, and barred insurance companies from excluding the sick from coverage.

Republicans consider it an example of huge government overreach and have spent seven years vowing to overturn it.

The two party-line votes in committee are not the last obstacles before the AHCA can reach the House floor. It still has to be considered by the House budget committee and the terms of debate before the full chamber still need to be determined by the House rules committee.