WASHINGTON — Democrats and activists opposed to GOP health care legislation have unleashed a full-scale effort to stop the plan — but are finding it difficult to get anyone to pay attention.

Despite the stakes, critics say Republican efforts to hide the legislative process and a relentless tide of major news elsewhere have made it harder to draw attention to the issue.

"If you're a voter sitting at home looking at your newspaper’s front page, it’s possible to have no idea the 'Trumpcare' train is barreling down the tracks at you," Ben Wikler, Washington director of MoveOn, told NBC News in an interview.

If all goes according to the GOP plan, Republicans in Congress will send sweeping healthcare legislation that could affect coverage, cost and treatment for tens of millions of Americans to President Donald Trump’s desk before August. The House has already passed a bill and the Senate hopes to hold a vote on its own version as early as this month.

It's the home stretch for arguably the most important legislation in Congress since the Affordable Care Act.

"This is not a drill, this is a red alert," Senate Minority Leader Chuck Schumer (D-NY) said in a floor speech this week. "In a very short time, maybe only two weeks, the Republican majority may try to jam through a health care bill that no one in America has seen."

MoveOn and a variety of other grassroots groups are warning members that a bill is imminent and sounding the alarm with events, petitions and phone calls to senators. Democrats have been giving floor speeches, holding town halls, and tweeting all week about the expected legislation. But some are expressing frustration that their message is getting lost in the noise.

"Think of every Trump tweet as an attempt to get the media to not cover the destruction of the Affordable Care Act," Sen. Ed Markey (D-Mass.) told reporters at a press conference highlighting the House bill’s impact on opioid treatment on Thursday. "That's what’s going on."

For weeks, news coverage has been dominated by the ongoing scandal surrounding the White House’s firing of FBI director James Comey, including Comey’s own testimony last week, Attorney General Jeff Sessions’ on Tuesday, and Trump’s regular commentary on Twitter.

"When people ask me a question about Russia, I say, 'I'm happy to talk to you about it, but you’re going to have to listen to me talk about the health care challenge ahead,'" Sen. Ron Wyden (D-Ore.) said.

Sen. Chris Murphy (D-Conn.) tweeted during Tuesday’s hearing with the attorney general that followers should "focus 10% of your attention/outrage on Sessions testimony, 90% on the secret health care bill."

He told NBC News later that day that he expected it to be “the last week that you’ll hear Democrats focusing on anything other than health care."

On Wednesday, Congress was diverted by a horrifying attack on their own members at a baseball practice in Virginia that critically wounded House Majority Whip Steve Scalise (R-La.) The shooting halted many legislative activities and prompted a brief moment of bipartisan reflection from lawmakers, but the healthcare bill is moving on regardless.

"It looks like we’re still on track to have a vote before we leave [for July 4 recess]," Sen. Bob Corker (R-Tenn.) told reporters on Wednesday afternoon.

Democrats believe their case is strong if they can get it out.

The House bill would insure 23 million fewer people over the next decade, according to the nonpartisan Congressional Budget Office, while dramatically increasing premiums and out-of-pocket costs for older and low-income Americans. It would reduce Medicaid spending by over $800 billion and use the savings to help finance large tax cuts for wealthy Americans and medical industries, a shift that could squeeze benefits for low-income families, seniors in nursing homes, and children with disabilities. Even President Trump reportedly called the bill “mean” in a meeting with senators this week.

But that’s the House bill. The Senate bill is a moving target.

Even as Senate Republicans move toward a vote, almost nobody knows what’s in the bill. In a major break from normal procedure, Republicans are working out the details with a small working group, away from the normal spotlight of bipartisan committee hearings. Even some Republican senators have complained that they — and the public — have been left in the dark.

"If you get a copy of it, will you send me a copy?" Sen. Rand Paul (R-Ky.) told NBC News on Thursday.

The closed-door process means there are few developments that generate news stories, like public hearings with industry leaders and affected constituents, or new policy proposals for experts to evaluate. Instead, the opaque process itself is the main story.

"There’s a real danger here that this kind of legislating is going to become the new normal," Sen. Richard Blumenthal (D-Conn.) told reporters on Thursday, saying that Republicans were using the ambiguity around the bill to deflect scrutiny of its likely impact.

The House used similar methods to pass its health bill last month, releasing a final version within 24 hours of a vote and several weeks before the Congressional Budget Office could estimate its effects and cost.

Democrats and allied groups, fearing a repeat, have tried to draw attention to the secretive process, hoping they can pressure GOP leaders into being more forthcoming and build a backlash against the closed-door methods.

"The first message we’re asking [activists] to say to their senators is 'Show me the bill,'" Leslie Dach, campaign director of the Protect Our Care coalition, told NBC News. "It's just unconscionable that the Senate would vote on a bill that's going to affect people’s lives this way and one-sixth of the economy and purposefully refuse to let anyone see it."

Democrats say they’re confident they'll be able to draw more attention to the bill in the coming days.

"I think this issue is going to resume to front page status," Sen. Tim Kaine (D-Va.) told NBC News.

He added that the appointment of Special Counsel Robert Mueller gave them more room to discuss health care, since members were confident his investigation would be independent and thorough. As part of that effort, Kaine introduced a bill this week to help stabilize Obamacare exchanges, which are struggling in some states due to a combination of existing problems and mixed signals from the White House and Congress on payments owed to companies to cover costs for low-income customers.

Some grassroots activists have urged Democrats to take a more aggressive approach to disrupt normal Senate business in response to the GOP’s stealthy tactics. One online petition on CREDO Action calls on Democrats to use "every legislative tool at your disposal to block and resist Trumpcare."

Independent polling has consistently found the House bill is deeply unpopular, suggesting some of their message is breaking through despite the slew of news competing for Americans' attention. A Quinnipiac survey this month found respondents disapproved of the House bill by a massive 62-17 margin.

Sen. Joe Manchin (D-W Va.) told NBC News that the issue was “by far” the dominant concern expressed by his constituents in phone calls and town halls even as the media’s eye wandered elsewhere.

"I don’t have to draw attention it,” he said. "They come out in droves, they’re so hungry to talk about it."