How deeply is the National Treasury Employees Union involved in the IRS scandal?

It's just coincidence. The president of the National Treasury Employees Union meets with Obama one day before the harassment of the tea party groups begin. Jeffery Lord at the American Spectator makes this stunning report.

According to the White House Visitors Log, provided here in searchable form by U.S. News and World Report, the president of the anti-Tea Party National Treasury Employees Union, Colleen Kelley, visited the White House at 12:30pm that Wednesday noon time of March 31st.
The White House lists the IRS union leader’s visit this way:
Kelley, Colleen Potus 03/31/2010 12:30
In White House language, “POTUS” stands for “President of the United States.”
The very next day after her White House meeting with the President, according to the Treasury Department’s Inspector General’s Report, IRS employees — the same employees who belong to the NTEU — set to work in earnest targeting the Tea Party and conservative groups around America. The IG report wrote it up this way:
April 1-2, 2010: The new Acting Manager, Technical Unit, suggested the need for a Sensitive Case Report on the Tea Party cases. The Determinations Unit Program Manager Agreed.
In short: the very day after the president of the quite publicly anti-Tea Party labor union — the union for IRS employees — met with President Obama, the manager of the IRS “Determinations Unit Program agreed” to open a “Sensitive Case report on the Tea party cases.” As stated by the IG report.
The NTEU is the 150,000 member union that represents IRS employees along with 30 other separate government agencies. Kelley herself is a 14-year IRS veteran agent. The union’s PAC endorsed President Obama in both 2008 and 2012, and gave hundreds of thousands of dollars in the 2010 and 2012 election cycles to anti-Tea Party candidates.
Putting IRS employees in the position of actively financing anti-Tea Party candidates themselves, while in their official positions in the IRS blocking, auditing, or intimidating Tea Party and conservative groups around the country.

To me the question of White House involvement was not if but how. My suspicion has been focused on the IRS's office of general counsel but the coordination of attacks on tea party groups and Romney contributors through tax audits, OSHA inspections, ATF visits could have easily been facilitated through the respective unions of those organizations.