Robert Mueller made Nancy Pelosi’s job more difficult. When the special counsel spoke publicly for the first time this week, he reinforced a top finding of his investigation into the Russian intervention in the 2016 presidential election. He explained that he followed the Justice Department policy prohibiting the indictment of a president. Thus, the absence of an indictment wasn’t the equivalent of clearing President Trump of obstruction of justice. Mueller then sharpened his point, as he did in his lengthy report released in April. He stressed that if he had confidence the president did not commit a crime, he would have said so.

No surprise these words spurred additional Democrats, in the U.S. House and on the presidential campaign trail, to call for the start of an impeachment inquiry. That includes the chairs of the Rules Committee and the Homeland Security Committee. U.S. Rep. Tim Ryan, a Niles Democrat, reflected the mounting view, telling NPR that “Mueller basically said that he would have indicted the president but for the fact that the law would not allow it.” He added: We may be left with no choice but to impeach him.”

The impeachment drive includes more than the liberal firebrands. Even moderate types, such as John Hickenlooper, a former Colorado governor, have joined the ranks.

This isn’t what Speaker Pelosi has been advising. She has cautioned against an official impeachment inquiry, arguing that such a step is what the president wants. If she says, as she did this week during an appearance, that “nothing is off the table,’’ she also has warned against taking the bait. There is something to her concern, the president skilled at the politics of grievance or playing the victim, keen to portray his adversaries as going too far.

Perhaps the speaker has in mind the impeachment of Bill Clinton, House Republicans overreaching and the public recognizing as much. No doubt, she is concerned about holding her majority, captured last fall by Democrats winning in districts the president carried two years earlier. Put that in jeopardy when the Republican majority in the Senate would prove a lock for the president?

All of this political calculation offends many who see the House with a constitutional duty to proceed in view of the president’s impeachable offenses, his efforts to impede the FBI and later the Mueller investigation, including urging aides to falsify the record. U.S. Rep. Justin Amash, a Michigan Republican, has arrived at such thinking.

Yet there is something Pelosi asks her caucus to weigh — the potential for an impeachment inquiry to make Trump stronger. Thus, her concern goes beyond futility in the Senate. What if events work to secure Trump a second term? That would be a Democratic calamity.

The speaker understands that impeachment is a political matter, more than anything. Congress defines “high crimes and misdemeanors.” Thus, Pelosi also accounts for the deep partisan divide. Impeachment means seeking to overturn the result of a presidential election. That is consequential, even when the incumbent did not prevail in the popular vote. So the circumstances point to what the speaker told her audience on Wednesday: “ … we do want to make such a compelling case, such an ironclad case, that even the Republican Senate … will be convinced of the path we have to take as a country.”

So House Democrats have an obligation to conduct the necessary oversight, especially in addressing the Mueller findings and in examining the president’s vast business dealings for conflicts of interest. That may not be enough now for some in their ranks. It is the way to the hard-won consensus the speaker rightly wants to see.