The momentum to impeach President Trump is accelerating.

On Thursday, Congressman Jerrold Nadler (D-NY) filed a “resolution of inquiry” that amounts to the first legislative step toward impeachment.

A new poll shows that registered voters are evenly split, at 46-to-46 percent, on whether they “support” or “oppose” impeaching Trump. Just two weeks ago, the pro-impeachment figure was 35 percent.

Since inauguration, more than 800,000 people have signed a petition in the first stage of the Impeach Donald Trump Campaign, which will soon involve grassroots organizing in congressional districts around the country.

Under the Trump presidency, defending a wide range of past gains is both necessary and insufficient. Fighting for impeachment is a way to go on the offensive, directly challenging the huge corruption that Trump has brought to the White House.

From the outset, President Trump has been violating two provisions of the U.S. Constitution -- its foreign and domestic “emoluments” clauses. In a nutshell, both clauses forbid personally profiting from presidential service beyond receiving a government salary.

Some believe that the Republican-controlled Congress is incapable of impeaching Trump, but history tells us what’s possible when a president falls into wide disrepute. On July 27, 1974, seven GOP representatives on the 38-member House Judiciary Committee voted to impeach a fellow Republican, President Richard Nixon.

As for objections that impeaching and removing Trump from office would make Mike Pence the president, that concern is apt to bypass one set of key considerations after another. Along the way, in political terms, people need to think through the implications of the fact that Trump could only be removed from office with the help of many votes from Republicans on Capitol Hill.

Even if every Democrat in the House voted in unison to impeach Trump, impeachment would only be possible if at least two-dozen Republican members of the House voted in favor. Likewise, a vote in the Senate (requiring two-thirds) to remove Trump from the presidency would only be successful if at least 19 Republican senators voted for conviction. Such events would badly splinter and damage the Republican Party -- causing divisive bitterness, putting GOP leaders back on their heels and hobbling a Pence presidency.

Arguably most important of all, democracy requires that no one be above the law -- a principle that’s most crucially applied to the holder of the most powerful office in the U.S. government. Extreme abuse of power from the top of the government must be seen and treated as intolerable.

The Constitution that Trump continues to flagrantly violate is supposed to be “the supreme law of the land.” To give Trump a pass would be to wink at his merger of vast personal wealth and corporate holdings with vast governmental power.

From the grassroots, it’s crucial for constituents to push back with determination. As the Impeach Donald Trump Now campaign’s website documents in detail, Trump’s personal riches are entangled with countless policy options for his administration. That precedent must be resisted and defeated.

So far, the Democratic Party’s leadership in Congress has shown scant interest in impeaching Trump. With escalating pressure from constituents, that may soon change.

Congressman Nadler’s unusual resolution of inquiry will be able to avoid some of the standard roadblocks in the House. As his website explains, “A Resolution of Inquiry is a legislative tool that has privileged parliamentary status, meaning it can be brought to the floor if the relevant Committee hasn’t reported it within 14 legislative days, even if the Majority leadership has not scheduled it for a vote.”

Nadler has just put a big toe in the impeachment water. Yet no members of the House have taken the plunge to introduce an actual resolution for impeachment. They will have to be pushed.