Joe Biden will have Iowa virtually to himself in the coming days as several of his top presidential rivals decamp to Washington to participate in President Donald Trump's impeachment trial. But as Biden seeks to leverage his freedom with a final campaign blitz in the critical early voting state, he and his advisers know that the proceedings in Washington could overshadow any closing case they try to present.

Although he will be far from Capitol Hill, Biden is intertwined with the root cause of Trump's impeachment case: The president pressured the Ukraine president to declare a public investigation of Biden and his son Hunter Biden based on discredited theories about the younger Biden’s foreign business dealings.

Biden himself sought to sidestep the issue during public appearances on Monday. But aides to the former vice president worked furiously to get ahead of any effort by Senate Republicans to use the trial to malign him.

Democratic presidential candidate former Vice President Joe Biden speaks at the Brown & Black Forum at the Iowa Events Center, Monday, Jan. 20, 2020, in Des Moines, Iowa. (AP PhotoAndrew Harnik)

Democratic presidential candidate former Vice President Joe Biden speaks at the Brown & Black Forum at the Iowa Events Center, Monday, Jan. 20, 2020, in Des Moines, Iowa. (AP PhotoAndrew Harnik)

Kate Bedingfield and Tony Blinken, top campaign aides to Biden, distributed a memo to the media saying Trump “is the only American president to have weaponized foreign and national security policy in an attempt to coerce a foreign country into lying about a rival presidential candidate.”

The document reflects that Trump’s claims have no basis and underscores the Biden campaign’s long-established strategy of aggressively countering Trump’s broadsides, a lesson his aides say they learned from Hillary Clinton’s handling of Trump in 2016. But it is also an acknowledgment that Biden cannot necessarily control this story line, especially as some Republicans and conservative media push the idea, however unlikely, that the Bidens should testify before the Senate.

With that in mind, the memo urged media not to repeat a “malicious and conclusively debunked conspiracy theory” from the White House and GOP claiming that the Bidens engaged in wrongdoing when Hunter Biden served on the board of a Ukrainian energy firm while his father handled U.S. foreign affairs in the same country.

Democratic presidential candidate former Vice President Joe Biden appears at the Brown & Black Forum at the Iowa Events Center, Monday, Jan. 20, 2020, in Des Moines, Iowa. (AP PhotoAndrew Harnik)

Democratic presidential candidate former Vice President Joe Biden appears at the Brown & Black Forum at the Iowa Events Center, Monday, Jan. 20, 2020, in Des Moines, Iowa. (AP PhotoAndrew Harnik)

Indeed, Trump’s unsupported assertions have always depended on the discredited accusation that the elder Biden pressed for the firing of top Ukrainian prosecutor Viktor Shokin to spare his son’s company, Burisma, from scrutiny. Ousting Shokin was, in fact, the official position of the U.S. government and its Western allies, including European Union nations and the International Monetary Fund leadership, because Shokin was believed to be incompetent or corrupt himself.

House impeachment articles now being considered by the Senate are pegged to disclosures that Trump held up congressionally appropriated aid to Ukraine as he pressured President Volodymyr Zelenskiy to announce an investigation into the Bidens.

The Biden campaign insists that Trump’s trial won’t distract from the former vice president’s campaign effort and can be a boon to Biden’s argument that he is the Democrat with the best shot to defeat Trump in November.

“It’s certainly not something people talk about at town hall meetings,” insisted senior campaign adviser Anita Dunn. “It illustrates the lengths to which Donald Trump will go not to run against Joe Biden.”

Yet there are instances from the campaign trail showing potential risks for Biden.

In late December, he spent several days dealing with questions about whether he’d testify if called. He eventually told a voter at one of his events that he’d comply with a subpoena, though he sees no legal basis to be called, because the impeachment case against Trump is about the president’s actions, not Biden’s or his son’s. It now seems unlikely that the Bidens will be called. Senate Majority Leader Mitch McConnell has indicated he prefers a quick trial that is virtually guaranteed to end without Trump being convicted and removed from office.

Earlier in December, Biden angrily rebuked an Iowa voter who accused him of “selling access to the president” and getting Hunter “a job and work for a gas company that he had no experience” to justify. Biden called the man “a damn liar.” He offered the usual details during the campaign event and to reporters afterward: Hunter Biden joined the Burisma board without notifying his father; there’s no law preventing a vice president’s son from taking international posts, just as Trump’s children still advance his real estate interests abroad; and Ukrainian officials have said they found no wrongdoing in Hunter Biden’s service on the board.

Yet the result was a new round of headlines and a day of cable news coverage involving Trump, Biden and Ukraine. And, on that day at least, it overshadowed what would have been a significant story for Biden: an endorsement from former Secretary of State John Kerry, the 2004 Democratic presidential nominee.

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AP National Political Writer Steve Peoples in Des Moines, Iowa, contributed to this report.

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