McGinnis points out that:
One of the best disruptions of Donald Trump has been his decision to nominate many officials to the Cabinet who have been enormously successful in business. Such appointees have run major organizations and thus can use their substantial management experience to impose order on the sprawling government bureaucracy. They also bring the perspective of business into the heart of government. A commercial republic can thrive only if, from time to time, officials set about lifting off the dead weights that democratic practices tend to place on the economy.
It is thus disheartening, if not surprising, that many Democrats in the Senate now want to eliminate most of the tax law that facilitates the transition of business people to government. This law permits appointees to an administration to defer their capital gains on the stock they must sell to avoid conflict of interest. It thus encourages wealthy individuals to take government posts, because otherwise they would face an unpalatable choice: Pay a huge capital gains bill or hold on to stock that would create conflicts of interest in their new positions. The legislation greatly aids in eliminating conflicts of interest, because in exchange for the tax deferral, appointees must put their money in treasuries or index funds.
Thus, it is not an interest in good government, but in insular government that is behind the push to change this law.
It's basically a reverse John Galt move: the party of big government trying to ensure that only career government and K Street types can afford to do public service. Go read the whole thing.