WASHINGTON ― It’s no exaggeration to say the biggest flashpoint in the Democratic presidential race thus far has been health care ― namely, whether the United States should adopt “Medicare for All” ― but there’s a reality that hardly anyone is talking about: Congress.

While differences between candidates could manifest themselves in plenty of ways in office, any Democratic president would have an extremely tough time actually enacting systemic changes like Medicare for All. Lost in all of these health care debates between presidential contenders is that the resulting health care policies would probably all look very similar, regardless of which person wins.

Every Republican and most Democrats in Congress publicly oppose Medicare for All. And while those numbers have certainly been shifting, there is almost certainly a critical mass of Democrats who would join Republicans to block a single-payer health care system in the House ― let alone the Senate, where Republicans are likely to retain the majority, or at least be a vote or two away from it.

“You gotta get 218 votes on the floor of the House to do anything. And then you’ve gotta figure out a way to get, you know, theoretically, 60 votes in the Senate,” Rep. Dan Kildee (D-Mich.), the chief deputy whip of the Democratic caucus, told HuffPost on Thursday, speaking of the majority vote threshold to pass bills in the House and the filibuster-proof majority in the Senate.

“I don’t think that means we don’t have big ideas that candidates put out and pursue them,” Kildee continued. “But yeah, we have to make sure that we’re not creating some sort of an expectation that electing a president means that the entire agenda is just sort of self-actualizing.”

You gotta get 218 votes on the floor of the House to do anything. And then you’ve gotta figure out a way to get, you know, theoretically, 60 votes in the Senate. Rep. Dan Kildee (D-Mich.)

Voters may understand that part. President Donald Trump had to reckon with the realities of governing when, after passing an Obamacare repeal dozens of times when there was a Democratic president in control of the White House, Republicans couldn’t repeal the law when it came time to do it for real.

Anyone who thinks electing Sen. Bernie Sanders (I-Vt.) president means that Medicare for All would become law has an unrealistic view of lawmaking. And it’s not just health care. Every component of his agenda that requires Congress would be a tough slog. But what even more sophisticated voters might not understand is how resigned some of the most liberal voices in Congress are to their inability to get items like Medicare for All.

“A president can’t wave a magic wand and pass any legislation they want,” Rep. Alexandria Ocasio-Cortez (D-N.Y.) told HuffPost this week.

Ocasio-Cortez ― one of the most outspoken advocates for Medicare for All ― said she thought voters understood there was an “inherent check” on the president’s ability to actually change things like our health care system. And she argued that the realities of governing were actually an argument for someone like Sanders, as he’d be able to push Democrats and resulting changes further left.

But Ocasio-Cortez is also realistic about how far even a President Sanders could actually move Congress.

“The worst-case scenario? We compromise deeply and we end up getting a public option. Is that a nightmare? I don’t think so,” she said.

Ocasio-Cortez stressed that just getting a public option for health care wasn’t the left’s ultimate goal. But she also said she wasn’t here to railroad other members with differing viewpoints on health care ― she just thinks it helps to have a president who has a more ambitious platform than Congress so that Democrats could stretch what’s possible.

Joe Raedle via Getty Images Anyone who thinks electing Bernie Sanders president means that "Medicare for All" would become law has an unrealistic view of lawmaking.

What’s possible, at least in the near term for any Democratic president, seems extremely limited.

There are currently more than 70 members out of 435 in the “Medicare for All Caucus,” but those numbers also seem to include lawmakers who support a buy-in option for Medicare, rather than eliminating private insurance entirely. And Democrats have consistently shown a deference to the most vulnerable and moderate members ― the so-called “majority makers.”

“The gauge for how far we can go on some of these issues is around the 40 people that have given us the majority,” Rep. Tim Ryan (D-Ohio), a former presidential candidate himself, told HuffPost on Thursday.

“This whole system is built on everyone operating in their own self-interest, and nobody knows their self-interest better than they do,” Ryan said of the Democrats who beat Republicans to take the majority.

Those Democrats, even the ones who may personally believe in Medicare for All, seem to be very cautious about getting too far in front of their constituents.

Rep. Tom Malinowski (D-N.J.), who beat incumbent Republican Leonard Lance in 2018 despite Lance voting against the GOP health care bill, chose his words carefully when HuffPost asked him about Medicare for All.

“You know where the consensus in the [Democratic] Caucus is ― it’s around improving the Affordable Care Act,” Malinowski said.

And Rep. Lauren Underwood (D-Ill.), who took down former Rep. Randy Hultgren (R-Ill.) in 2018, essentially refused to say whether she supported Medicare for All, insisting that supporting or opposing it wasn’t a binary choice.

When HuffPost pressed her on whether Medicare for All was her ultimate ambition, she said her end goal was to ensure that “every American has access to high-quality health care in this country.”

And when we pushed further ― mentioning that “access to care” was a favorite talking point of former House Speaker Paul Ryan’s ― Underwood said she would “really like to not be included in this piece, because there’s some kind of framing agenda.”

Whether Underwood likes our “framing agenda” or not, she’s in a tough district to support Medicare for All. She represents the western suburbs of Chicago, which has a Partisan Voting Index score of R+5. And the realities of holding seats in districts like that may preclude supporting Medicare for All.

But according to Progressive Caucus co-chair Pramila Jayapal (D-Wash.), there are many Democrats who personally support Medicare for All and just feel it’s unrealistic and politically damaging to advocate for it.

If we’re electing Bernie Sanders, we can get there. Rep. Pramila Jayapal (D-Wash.)

Jayapal would have a very good sense of support for Medicare for All; she’s the primary sponsor of the most prominent single-payer bill in Congress.

She did say she thought a Sanders presidency would help significantly with the potentially poor politics of Medicare for All. “If we’re electing Bernie Sanders, we can get there,” Jayapal said.

And other Democrats suggested that Sanders would represent a sort of tipping point because he could accomplish much of his agenda through executive orders.

“A lot of the right-wing, extreme, very hateful policy agenda of the current administration was done through the executive office,” Rep. Rashida Tlaib (D-Mich.) said.

But Tlaib did say that the “transformative change” happens outside of Congress. And she seemed to understand that something as big as Medicare for All would be a long road.

That seems to be the consensus from progressives in Congress.

As Rep. Jared Huffman (D-Calif.) put it, Democrats are still years away from reaching a critical mass on Medicare for All. And he noted that there would be “tremendous resistance” to enacting much of what Sanders and other progressives in Congress want.

“That’s just the nature of our political tapestry,” he said.