One of our committee’s first acts of this new Congress — that is, once Republicans quit stalling and finally appointed their members — was to authorize the release of our dozens of interview transcripts to Special Counsel Robert Mueller. Coming up, we will have Michael Cohen — President Trump’s longtime personal attorney and fixer — back in for more testimony on Feb. 28, now that he has pleaded guilty to lying to us the first time. More witness interviews will follow in coming months.

All of this should’ve happened a long time ago. Our investigations probably could’ve been completed by now, but former Chairman Devin Nunes, R-Tulare, wielded the shovel that spent two years burying critical evidence to protect President Trump. With Nunes now relegated to ranking member, we must see what we can unearth.

The transcripts we sent Mueller will ensure he knows exactly what witnesses told us, and whether that conflicts with what they or others told him. But we never should have been conducting “take-them-at-their-word” interviews with these people to start with — few if any were trustworthy enough to deserve that. As they spoke to us, we should have been subpoenaing phone logs, bank records and other documents that could’ve confirmed or disproved their stories.

It wasn’t a total loss; we did learn some valuable lessons. We know that Trump campaign officials and family members were approached by or met with Russian emissaries offering dirt on Hillary Clinton, Trump’s 2016 electoral opponent, yet they never informed the FBI.

Most of us probably hoped this would be common sense, but unfortunately, it seems we must specify it. I’ll be introducing a broader version soon, not as a rebuke to President Trump or as an effort to relitigate the 2016 election, but as a preventative, defensive measure for the future.

But this is just one facet of learning what happened and making sure it can never happen again. And two years of delay, obstruction, and obfuscation come at a high cost.

Records may have been lost or destroyed. Witnesses who could’ve been held to account the first time are now forewarned about the avenues of our questioning, and so have had opportunity to align their stories. And the nation has grown increasingly exhausted, beaten down by the president’s constant gaslighting and distractions.

Yet it isn’t too late. We can still conduct real, impartial, unwavering oversight. This isn’t a diversion from Congress’ other work — this is part and parcel of the job we were sent to Washington to do.

And if the president thinks that we would consider dropping investigations vital to our democracy’s health in exchange for his cooperation on legislation — as he demanded in his State of the Union address — he has another thing coming. He was given two years to blow his smoke; now the wind is rising to clear our skies once and for all.

If the president, his enablers in Congress, or anyone else wants to see a swift end to these investigations, they should stop obstructing and start cooperating. That’s how we get the work done, and that’s how we protect our nation for years to come.

Rep. Eric Swalwell, D-Castro Valley, chairs the Intelligence Modernization and Readiness Subcommittee of the House Permanent Select Committee on Intelligence. He also serves on the House Judiciary Committee.