DW: What does the ouster of Donald Trump's campaign manager Corey Lewandowski tell us about the state of the Trump campaign and the Republican Party?

Thomas Mann: Nothing that we didn't already know. Lewandowski was ill-equipped to run a general election campaign, but his hiring and firing were controlled by Trump. Trump's campaign is scandalously undeveloped, understaffed, and underfinanced. It is hard to see how this firing will make a measurable difference. Trump himself is the source of the problems.

What should we know about Paul Manafort, the man now solely in charge of the Trump campaign?

Manafort is a colleague of Roger Stone, one of slimiest political consultants/lobbyists in the business. Manafort hasn't worked for a US presidential campaign in decades. He's been advising tyrants around the world. He is part of the old, dark Republican political establishment.

Will the Trump campaign change now that the controversial Lewandowski is gone? If so, how?

I doubt it. He's relying on the Republican National Committee (RNC) for fundraising, targeting and voter mobilization and still planning to generate his own free media. Trump is running his own show and it will be a sight to behold.

Thomas Mann is a senior fellow in governance studies at the Brookings Institution and a resident scholar at the Institute of Governance Studies at the University of California in Berkeley. His latest book co-written with Norman Ornstein is "It's Even Worse Than It Looks: How the American Constitutional System Collided With the New Politics of Extremism."

The interview was conducted via email by Michael Knigge.