Trump owes the American people some answers. Democrats should force him to provide them. (REUTERS/Joshua Roberts/File Photo)

As a Democratic Senate aide for the past seven years, I had a front-row seat to an impressive show of obstruction. Republicans, under then-Senate Minority Leader Mitch McConnell, decided they would oppose President Barack Obama and Senate Majority Leader Harry Reid at every turn to limit their power. And it worked: They extorted concessions from Democrats with threats of shutdowns, fiscal cliffs and financial chaos. I know firsthand that Democrats’ passion for responsible governance can be exploited by Republicans who are willing to blow past all norms and standards.

Now we have a president who exemplifies that willingness in the extreme. Partly, this explains why he faces more questions about his legitimacy than any president in recent history and why he drew three times as many protesters as inauguration attendees last weekend. But in something of a mismatch, Republicans’ unified control of government means that the most effective tool for popular resistance lies in the Senate — the elite, byzantine institution envisioned by the founders as the saucer that cools the teacup of popular opinion.

Senate Democrats have a powerful tool at their disposal, if they choose to use it, for resisting a president who has no mandate and cannot claim to embody the popular will. That tool lies in the simple but fitting act of withholding consent. An organized effort to do so on the Senate floor can bring the body to its knees and block or severely slow down the agenda of a president who does not represent the majority of Americans.

The procedure for withholding consent is straightforward, but deploying it is tricky. For the Senate to move in a timely fashion on any order of business, it must obtain unanimous support from its members. But if a single senator objects to a consent agreement, McConnell, now majority leader, will be forced to resort to time-consuming procedural steps through the cloture process, which takes four days to confirm nominees and seven days to advance any piece of legislation — and that’s without amendment votes, each of which can be subjected to a several-day cloture process as well.

McConnell can ask for consent at any time, and if no objection is heard, the Senate assumes that consent is granted. So the 48 senators in the Democratic caucus must work together — along with any Republicans who aren’t afraid of being targeted by an angry tweet — to ensure that there is always a senator on the floor to withhold consent.

Because every Senate action requires the unanimous consent of members from all parties, everything it does is a leverage point for Democrats. For instance, each of the 1,000-plus nominees requiring Senate confirmation — including President Trump’s Cabinet choices — can be delayed for four days each.

While the tactic works well, as we’ve seen for the past eight years, there remains the question of strategy. Should Democrats be pragmatic and let Trump have his nominees on a reasonable timetable, so as not to appear obstructionist? So far, this has been their approach to some of Trump’s Cabinet picks.

But it’s also fair to say that, by nominating a poorly qualified and ethically challengedCabinet, Trump forfeited his right to a speedy confirmation process, and Democrats should therefore slow it down to facilitate the adequate vetting that Trump and Senate Republicans are determined to avoid by rushing the process before all the questionnaires and filings are submitted. Four days of scrutiny on the Senate floor per nominee, even after the committee hearings, is a reasonable standard for fulfilling the Senate’s constitutional responsibility of advice and consent.

Democrats can also withhold their consent from every piece of objectionable legislation McConnell tries to advance. With 48 senators in their caucus, they have the votes to block most bills. But even when Democrats don’t have the votes, they can force McConnell to spend time jumping through procedural hoops. This is the insight McConnell deployed against Reid to manufacture the appearance of gridlock, forcing him to use the cloture process more than 600 times.

Finally, Democrats can withhold their consent from Trump until they feel confident that foreign governments are not interfering in our elections. Credible reports hold that U.S. intelligence agencies are investigating whether Trump’s campaign cooperated with the Russian government on Vladi­mir Putin’s personally directed meddling. Withholding consent from Trump’s agenda until an independent, bipartisan probe provides answers is not just reasonable; it’s responsible. If Democrats withhold consent from everything the Senate does until such a process is established, they can stall Trump’s agenda and confirmation of his nominees indefinitely. Sen. Richard Durbin has been a leader in demanding an independent investigation. But unless Democrats back their calls with the threat of action, McConnell will steamroll them and never look back.

Of course, it would be unwise to deploy this strategy blindly. The kind of universal obstruction pioneered by McConnell during Obama’s presidency is not in Democrats’ nature: They believe in the smooth functioning of government.

But Democrats’ concern with delivering results for their constituents is also part of who we are and something we should embrace. Even for innately cautious Democrats, some issues demand dramatic action. If Trump wants to put their concerns about his legitimacy to rest, he can reach out with consensus nominees and policies, and come clean about his ties to Russia and his tax returns (which may show whether he has compromising financial debts to Russian interests). Until then, Democrats can stand up for America by withholding their consent.