Stephen Miller, Donald Trump’s former top adviser, will give testimony to the January 6 committee today.

After the former president’s daughter and son-in-law, Ivanka Trump and Jared Kushner, both former senior White House advisers, gave their own testimony in recent weeks, the House investigation into the Capitol riot is lapping at the Trump Oval Office’s doors.

It’s unclear whether Miller will appear in person or virtually before the nine-member bipartisan panel, according to two sources.

The fact that he’s showing up at all is a significant development, and it’s likely another major setback for Trump’s efforts to keep information about his movements on the day of the insurgency and subsequent attempts to overturn the presidential election he lost to Joe Biden under wraps.

After receiving a subpoena in November, Miller, who has been considered Trump’s top aide throughout his single term in office, has fiercely resisted previous efforts to compel him to testify. Miller had “participated in efforts to spread false information about alleged voter fraud,” according to Bennie Thompson, the Mississippi Democrat who chairs the panel at the time. This is the basis of Trump’s big lie that his election defeat was fraudulent.

It remains to be seen how cooperative Miller will be with the testimony he has to offer. Last week’s House vote to hold former Trump advisers Peter Navarro and Dan Scavino in contempt for refusing to comply with their own subpoenas prompted Miller’s decision to appear.

If Miller cooperates, his testimony could be some of the most valuable and compelling evidence the 6 January investigation has gathered to date about Trump’s role in the deadly insurgency.

Miller was by Trump’s side throughout his presidency, a fiercely loyal and focused figure credited with devising some of the administration’s most divisive and harsh policies.

Miller, a far-right extremist known for his white nationalist and far-right views, was involved in almost every decision Trump made while in office, as well as the ultra-hardline immigration policies he would almost certainly have implemented if he had won a second term.

Analysts are wondering if Miller will be forthcoming or will instead invoke the fifth amendment to avoid questioning because of his loyalty to his former boss and to Trumpism itself. Miller’s agreement to appear – which neither he nor the panel has confirmed – has already sparked speculation that it was simply a ruse to avoid the fate of Scavino and Navarro.

Miller’s appearance sharpens the committee’s focus in the final stages of its investigation on Trump’s inner circle, which has vociferously promoted the big lie that his election defeat in 2020 was rigged. The former president’s actions on the day of the insurgency and afterward have been scrutinized, with the most recent revelation being that calls he made on January 6th were hidden from the official log.

The investigation also looked into an alleged illegal scheme pushed by Trump and his supporters to put forward fake electors in order to overturn Joe Biden’s electoral college victory.

The panel has stated that public hearings will most likely take place this spring, with a report due before this year’s midterm elections. According to polling, Republicans are in a strong position to gain a majority in the House, at which point most observers believe the investigation will be terminated.