Complex sentence: Such a phenomenon has had a presence in the White House at least as early as the presidency of Bill Clinton under the advice of Sidney Blumenthal, Clinton's staff continued to engage in campaign methodology once in office, using polling for assistance in making decisions.
Split into simpler sentences: Such a phenomenon has had a presence in the White House at least as early as the presidency of Bill Clinton. Under the advice of Sidney Blumenthal, Clinton's staff continued to engage in campaign methodology once in office, using polling for assistance in making decisions.