Donald Trump, the weak and frightened president who makes his most important decisions based on lists provided to him by right-wing zealots and his corporate overlords, plans to name a nominee to replace Justice Anthony Kennedy on the US Supreme Court on July 9.

Mitch McConnell, the calculating US Senate majority leader who delayed deliberations on President Barack Obama’s legitimate Supreme Court pick in order to steal a place on the bench, will put the confirmation of Trump’s pick on a legislative fast track.

Trump and McConnell will try to overwhelm opposition with a shock-and-awe strategy that relies entirely on fostering a sense that their attempt to redefine the judicial branch of the federal government cannot be stopped.

But it can be stopped. This is the essential understanding that must be embraced by Americans who, in these unsettled times, seek to maintain the rough outlines of a system of checks and balances. Trump’s nominee must be approved by McConnell’s Senate.

The majority leader will, of course, break every rule in order to thwart Democratic opposition. He will, as well, employ sly backroom strategies to pressure the Senate’s 51 Republicans to vote for the nominee Trump is expected to select from the vetted list of 24 judges (and Utah Republican Senator Mike Lee) that was assembled for him by political strategists for the special-interest groups that seek to forge an activist majority on a Supreme Court that can then dismantle essential protections for civil rights and civil liberties while increasing the power of corporations. No mystery there.

But McConnell is not guaranteed to get the 51 votes he needs. He may not even get to 50—the magic number that would allow Vice President Mike Pence to cast the tie-breaking vote for transformation of the high court.

Here’s how the math works.

The Senate Democratic Caucus consists of 49 members: 47 Democrats and two independents (Maine’s Angus King and Vermont’s Bernie Sanders). If the caucus is united in opposition to a Trump nominee—certainly not an assured circumstance, but a possible one if defenders of an independent judiciary dial up their advocacy—then the opposition needs, at most, two Republicans to derail McConnell and the president.

While Pence can break ties, he cannot vote to create a tie. If the opposition can get a 51-49 vote against the president’s nominee, the nominee is blocked. If one Republican does not vote (presumably Arizona’s ailing Senator John McCain), then the opposition could combine 49 Democratic votes and one Republican vote to prevail on a 50-49 split.

Is this a realistic prospect? Absolutely. Holding 49 Democrats in line and getting one Republican—or, ideally, two—to take the side of right is certainly within the realm of possibility.

But the pursuit of this possibility will yield success only if it is grounded in realism. And underpinned by the hard work of state-based activism. A focus on Washington means little. A targeted and politically savvy focus on key states could mean everything.

So let’s begin by tossing aside fantasies that suggest Republican senators such as Jeff Flake of Arizona, Bob Corker of Tennessee, or Ben Sasse of Nebraska might act upon their frequent criticisms of Trump’s destructive tactics and policies.

These showboating fake mavericks can always be counted on to tout their independence. But they simply cannot be counted on to cast independent and responsible votes on questions that matter to America.

There’s nothing wrong with poking at the consciences of Flake, Corker, Sasse, and other Senate Republicans who play the game of suggesting that they have minds of their own. But the smart strategy for winning this fight is to focus energy and people power on the two Republicans who might realistically break with the administration and with McConnell. They are Maine’s Susan Collins and Alaska’s Lisa Murkowski.

Collins and Murkowski have already split with the rest of the caucus on critical issues such as health-care reform. McCain is also a wild card, but he is less likely to break with Trump on a Court pick; and his long battle with brain cancer has kept him off the Senate floor for most of the past year.

Collins has provided the greatest encouragement for the opposition. She’s a frustrating figure, who often gets big votes wrong. But this will be a definitional vote for the senator from a state that has not backed a Republican for president since 1988 and that has a resurgent Democratic Party. On Sunday, she told CNN’s State of the Union, “I would not support a nominee who demonstrated hostility to Roe v. Wade because that would mean to me that their judicial philosophy did not include a respect for established decisions, established law.”

There was plenty of wiggle room in that statement. But the fact is that, as NBC’s Hallie Jackson said Sunday, potential nominees “wouldn’t be on the list coming out from the Federalist Society, if you didn’t already know where they stood on that particular issue.” In other words, Trump will pick a nominee who has demonstrated sufficient hostility to Roe v. Wade to end up on a list cobbled together by the opponents of Roe v. Wade.

Collins cannot be allowed to have it both ways. She can and must be held to account by activists in Maine. Her opposition alone could prevent a Trump-selected, McConnell-supported justice from tipping the balance on the high court far to the right.

What of Murkowski? It’s trickier. She comes from a reasonably pro-Trump state, but she is a reasonably pro-choice senator. Murkowski has beaten the far right before, and she now says: “My standards for Supreme Court nominees are extremely high. It is my longstanding practice to carefully scrutinize the qualifications of judicial nominees and to cast an independent vote when judicial nominations come before the Senate. There is no doubt that the President’s nominee to succeed Justice Kennedy can expect exacting scrutiny from the Senate and that is the standard I will apply in evaluating the nominee.”

Murkowski has not provided quite as much encouragement as Collins for pro-choice forces, and for the broader coalition of opposition to a Trump pick. But she has created plenty of space for activists on the ground in Alaska to fill with messages that are tailored to the senator’s interests and concerns.

That’s the key to any calculus for blocking Trump’s Court pick. In order to secure “no” votes from wavering Democrats who are up for reelection this year (particularly North Dakota’s Heidi Heitkamp and West Virginia’s Joe Manchin, but also Indiana’s Joe Donnelly and Missouri’s Claire McCaskill), and to swing “possible” Republicans such as Collins and Murkowski, the opposition to Trump’s nominee must develop a state-based strategy. Instead of national messaging, the arguments for why responsible Republicans and red-state Democrats should block this Court pick must be grounded in the interests and issues of the states that are in play. Concerns about women’s rights and LGBTQ rights are going to be front and center, but the bill of particulars should also touch on abuses of presidential powers, privacy rights, worker rights, protection of public lands, agribusiness consolidation, and a host of other legal issues that might raise the right questions about the wrong nominee.

Mitch McConnell vows: “We will vote to confirm Justice Kennedy’s successor this fall.”

McConnell can manipulate the Senate rules and Trump can manipulate the media. But McConnell and Trump cannot manipulate the math. If 49 Democrats and two Republicans vote “no,” the nominee that Trump advances on July 9 will not be Justice Kennedy’s successor. Indeed, it is possible that just one Republican vote will be needed to block this Trump pick and to set the stage for a fight that might follow the 2018 election.

That’s doable.