Clearly, House of Representatives Speaker Nancy Pelosi smells blood in the water. Otherwise, she would not have launched an impeachment inquiry against President Donald Trump.

The question now is whether House Democrats circling to take a political bite out of Trump will attempt to ignore a potentially worse scandal.

For months, Pelosi, D-California, has resisted calls from the left wing of her party to begin impeachment proceedings against Trump. Last week, she apparently sensed controversy regarding U.S. relations with Ukraine might provide an opening against the president.

House Democrats plan to investigate contacts between Trump and Ukrainian President Volodymyr Zelenskiy. They are focusing on a July 25 phone conversation in which Trump discussed a situation involving former Vice President Joe Biden, currently the frontrunner for the Democratic nomination for president.

In his conversation with Zelenskiy, Trump referenced an event in March 2016, when Biden, representing the United States, traveled to Ukraine and told the country’s leaders then they would not receive $1 billion in promised U.S. aid unless the country’s chief prosecutor was fired.

Biden admits doing just that. But he and other Democrats insist the Ukrainian prosecutor was corrupt.

It happens that the prosecutor was looking into allegations of corruption involving Biden’s son, Hunter. Biden’s action brought that probe to an end.

At the time, Hunter Biden was being paid as much as $50,000 a month to serve as a board member for Ukraine’s largest private gas company, Burisma. The firm clearly was attempting to buy influence with then-President Barack Obama’s administration. Sensing the political fallout possible from the arrangement, Hunter Biden resigned his post this spring — as his father was preparing to run for president against Trump.

Trump’s phone call was an attempt to get the Ukrainian investigation involving both Bidens resumed. Pelosi and other Democrat leaders maintain the president’s action was improper use of U.S. clout for political reasons.

Pelosi’s party controls the House, so Democrats are in the driver’s seat on how the impeachment inquiry will proceed.

But they have opened a Pandora’s box. Any attempt to cover up Biden’s role in the affair will be seen through by voters. If the House investigation is to be viewed as anything other than what Trump says it is — a witch hunt — lawmakers cannot give Biden a free ride.