Chuck Schumer is in a spirited mood. "This is going to be one of the biggest fights of the next three, four months," the Senate minority leader said recently of the coming debate over tax cuts. "And Democrats are ready for it."

No doubt they are. But the relevant question is: Does their readiness even matter? Last month Mitch McConnell said he planned to bring taxes to the Senate floor under the budget reconciliation procedure. That would bypass the filibuster. The bill could pass by majority vote. No Democrats required.

And Republicans are unlikely to experience the defections over taxes that doomed them on health care. The health bill was a mess, a product of Republican confusion and infighting. There is no such uncertainty toward cutting taxes.

This is not to say that a cut is a done deal. Congressional Republicans may find a way to screw up. Fumbling the ball at the one-yard line is a specialty of theirs. But the prospect that GOP incompetence may rob the Trump administration of another legislative victory only underscores the fundamental point: Chuck Schumer's big words to the contrary notwithstanding, the Democrats are irrelevant to the power equation in Donald Trump's Washington.

That equation consists of five variables. None is called (D).

Donald Trump

The president, through sheer cultural weight, is the dominant figure on the world stage. Brian Stelter of CNN remarked on Thursday that Hurricane Harvey was the first story in months, perhaps years, to displace Donald Trump from the top headlines. If it takes an act of God to upstage you, you know you are famous. Trump's every word, every gesture, becomes the subject of controversy, discussion, analysis, rebuke, approval. He sets the agenda through social media and executive power. His wounds are largely self-inflicted. But he has also to rely on allies who are not entirely reliable.

Congressional Republicans

Paul Ryan and Mitch McConnell have helped the president with deregulation and reform of the Veterans Health Administration. But they have had difficulty with the larger questions of taxes, health care, immigration, and the budget. That is because Ryan and McConnell are traditional members of the Grand Old Party, whereas the president is the founding member of the Party of Trump. The two parties disagree over strategy, tactics, priorities, and policy.

Moreover, as Ramesh Ponnuru observes in the September 11, 2017, issue of National Review, the Grand Old Party is itself divided into 1) pro-business moderates like Ryan and McConnell, 2) Tea Party conservatives like Mark Meadows and Ted Cruz, and 3) working-class populists like Tom Cotton and Lou Barletta. For these groups to agree on a plan of action, in a way that satisfies President Trump, is a Herculean task.

The debate within the Grand Old Party, and between the GOP and the Party of Trump, is where the action is. Democrats are bystanders.

Radical Left

Whatever name they go by—antifa, cultural Marxists, social justice warriors, Black Lives Matter—it is the left, not the liberals, who are the most active and energetic counter-Trump force in America today. Marxists would say Trump and the left-wingers relate to one another in dialectical terms. He is the thesis, they the anti-thesis. The synthesis? Your guess is as good as mine.

Do not overlook the fact that the left is as opposed to the corporate liberals within the Democrat Party as it is to Trump. The Democrats denied the presidential nomination to Bernie Sanders and the party chairmanship to Keith Ellison. The Democrats worry about a backlash to the iconoclasm that would knock down statues of Christopher Columbus, Thomas Jefferson, and George Washington in the name of anti-racism. The Democrats cavil over whether to support the single-payer health care system embraced by Bernie Sanders, Kamala Harris, and the left. Meanwhile, Nancy Pelosi denounces the violence of antifa, and Dianne Feinstein is booed in San Francisco when she says that she hopes President Trump learns from his mistakes.

Reduced to its weakest position in decades, under heavy fire from its left flank, the Democratic Party has limited tools with which to respond to President Trump and the Republican majority. Its leaders Pelosi and Schumer have relied on legislative chicanery to slow down the Republicans in the Senate and verbal criticism from the sidelines. Increasingly the fight is not between Republicans and Democrats, but between the "right" symbolized by Trump and the "left" symbolized by black-shirted masked hooligans. And that is a fight Trump wins. Every time.

The media

It is not a condemnation of journalists or journalism to say that most of the damage done to the Trump administration has come from negative press coverage. The media amplify Trump's mistakes, highlight every criticism, publicize the tiniest details of the Russia investigations, dog him with tenacity not witnessed since Nixon. Of course he repays the favor. The media are not as powerful as they were during Watergate when there were only four television channels, three major papers, no Internet, and no social media. Do not doubt, though, the capacity of the press to shape public opinion and, in particular, shame elites of both parties into behaving like good liberals.

The fifth variable in our set is the most opaque, since it operates largely outside public scrutiny. It is also the most unpredictable, because its motives and objectives are unknown. And it is potentially the most important, because it has the power to reduce the strength of, if not remove altogether, one or two of the other variables. Its name is Robert Mueller.