Reid also used that letter to demand an update from the FBI on any links between Donald Trump and the Russian government.
One Republican Senator swung right back at Reid, as Sen. Tom Cotton (R-AR) called Reid a disgrace.
That was just the tip of the iceberg, as Republicans and Democrats in Congress quickly stepped up their own verbal broadsides at the other party.
"If you don’t want the FBI involved in elections, don’t nominate someone who’s being investigated by the FBI!" said Rep. Jeff Duncan (R-SC) on Twitter.
"As the FBI reopens its investigation, Hillary Clinton has no one but herself to blame," Speaker Paul Ryan chimed in.
But Democratic lawmakers were having none of that.
"FBI Director James Comey's letter to Congress doesn't give us any useful information — it just serves Republican attacks against Hillary," said Sen. Tim Kaine (D-VA) - Clinton's running mate.
"Just ten days before a Presidential election, the American people deserve more disclosure without delay," a group of Democratic Senators wrote in a letter to the FBI chief.
In Florida, Hillary Clinton told voters that she was not going to be "knocked off course" by the renewed focus on her emails.
"You know, there's a lot of noise and distractions," Clinton said on Sunday, as she vowed to stay focused on the concerns of voters.
But the email story was eating up most of the political oxygen over the weekend, and Trump was more than happy to pile on, calling the emails on a laptop held by ex-Rep. Anthony Weiner (D-NY), the "mother lode."
"We only have Crooked Hillary to beat," Trump said to cheers at a stop in New Mexico on Sunday night.
"I think the least of her problems right now is this race," as the crowd chanted, "Lock her up!"
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