Lets put two year into perspective for investigating a sitting president:
1992
The Whitewater Development Corp is dissolved, leaving Bill and Hillary Clinton with a loss of more than $40,000.
January 1994
Attorney General Janet Reno appoints Robert Fiske Jr. as the independent counsel in charge of investigating financial irregularities in the dealings of the Whitewater property company. The Clintons, and their business partners, James and Susan McDougal, are implicated.
August 1994
Fiske is replaced by the more conservative Kenneth Starr as the independent counsel investigating the Whitewater scandal.
July 29, 1998
President Clinton decides to testify voluntarily before the prosecutor over the allegations that he committed perjury in covering up a sexual affair with Ms Lewinsky.
October 5, 1998
The House Judiciary Committee votes to launch a congressional impeachment inquiry against President Clinton.
October 8, 1998
The House of Representatives vote for impeachment proceedings to begin against Clinton. The House judiciary committee will be given wide powers to draw up detailed charges against Mr Clinton, based on 11 allegations by the independent counsel Kenneth Starr in his report on the Monica Lewinsky affair.
Clinton impeachment timeline | US news | The Guardian