A trove of IRS emails show top official Lois Lerner had a deep commitment to the Democratic Party and a significant dislike for the new conservative grassroots groups that formed under the Tea Party banner and sought tax-exempt status from the agency.

"Crazies" and "a--holes," were the blunt terms Lerner used to describe conservatives, who, with a Supreme Court decision striking down the campaign finance reform law, were bringing about "an end to America," she wrote.

The emails are included in a bipartisan report issued Wednesday by the Senate Finance Committee, which cited "gross mismanagement" and also "personal politics" as the root cause of the IRS mishandling of tax-exempt applications from Tea Party organizations.

Democrats on the panel emphasized the mismanagement, declaring there was no evidence the groups were singled out because they were conservative. They cited lack of training, lack of oversight and ineptitude as the main culprits in the mishandling of hundreds of tax-exempt applicants that were subjected to extra scrutiny and delays.

"The results of this in-depth, bipartisan investigation showcase pure bureaucratic mismanagement without any evidence of political interference," said Sen. Ron Wyden of Oregon, the top Democrat on the finance panel.

But Lerner, the former top official who oversaw tax-exempt groups, showed a true dislike for conservative-leaning organizations, according to her email conversations with her husband and associates.

"Well, you should hear the whacko wing of the GOP," her husband, Michael Miles, wrote to Lerner in November 2012.

"The US is through; too many foreigners sucking the teat; time to hunker down, buy ammo and food, and prepare for the end. The right wing radio shows are scary to listen to."

Lerner responds, "Great. Maybe we are through if there are that many a--holes."

Lerner declares "WooHoo" in another November 2012 email after learning Democrats held on to the Senate majority.

At one point in 2011, Lerner contemplated auditing a group tied to Bristol Palin, the daughter of Tea Party favorite and former Republican vice presidential nominee Sarah Palin.

According to the Finance Committee report, Lerner began weighing the audit "upon receiving an article" that said a teen pregnancy organization would pay Palin more $332,500.

Finance Committee Republicans said Lerner's treatment of Crossroads GPS, a conservative group founded by GOP strategist Karl Rove, "shows her bias against conservative organizations that sought tax-exempt status — and her close connections to outside liberal advocacy groups."

According to the report, emails show Lerner singled out Crossroads GPS for special scrutiny after outside liberal groups and House Democrats complained about the group's political activity.

Emails show Lerner repeatedly intervening with the decisions made by her subordinates not to audit the group.

"You should know that we are working on a denial of the application, which may solve the problem because we probably will say it isn't exempt," Lerner said in one email to a subordinate. "Please make sure all moves regarding the [organization] are coordinated up here before we do anything."

The finance panel sifted through thousands of emails from Lerner, including 1,300 messages that were recovered after the IRS declared them lost due to a damaged hard drive.

Lerner served as director of exempt organizations from 2006 until 2013, when she was placed on administrative leave after an inspector general's report cited targeting of conservative tax-exempt applicants under her watch.

While Lerner has denied wrongdoing and has declined to answer questions before congressional investigators, her emails clearly show her partisan leaning.

"There can be little doubt that Lois Lerner's personal political views directed the course of IRS interactions with a large number of tax-exempt organizations," Finance Committee Republicans concluded in the report. "The IRS's treatment of these organizations was almost universally consistent with Lerner's personal political views this is, supporting Democratic candidates and opposing conservative tax-exempt organizations that engaged in political speech. Conservative organizations that sought to participate in the nation's political discourse, such as the Tea Party, drew the strongest ire from Lerner."

But Democrats on the committee filed their own report that included evidence, they say, showing that only mismanagement, and not politics, were at play.

Democrats said the 2013 inspector general's report that found conservative groups were singled out by the IRS actually "contributed to a misimpression that the controversy was politically motivated."

Democrats said interviews with 32 IRS employees and the review of 1.5 million IRS documents "found no evidence of political motivation driving the heightened scrutiny of Tea Party and conservative groups and the subsequent delays in processing their tax-exempt applications."