paid may be conditioned upon an appeal to the
Commissioner and his refusal to refund.[193] There was no denial of due
process when Congress took away the right to sue for recovery of taxes,
where the claim for recovery was without substantial equity, having
arisen from the mistake of administrative officials in allowing the
statute of limitations to run before collecting the tax.[194] The denial
to taxpayers of the right to sue for refund of processing and floor
taxes collected under a law subsequently held unconstitutional, and the
substitution of a new administrative procedure for the recovery of such
sums, was held valid.[195] Congress may cut off the right to recover
taxes illegally collected by ratifying the imposition and collection
thereof, where it could lawfully have authorized such exactions prior to
their collection.[196]

CONGRESSIONAL POLICE MEASURES

Numerous regulations of a police nature, imposed under powers
specifically granted to the Federal Government, have been sustained over
objections based on the due process clause. Congress may require the
owner of a vessel on which alien seamen suffering from specified
diseases are brought into the country to bear the expense of caring for
such persons.[197] It may prohibit the transportation in interstate
commerce of filled milk,[198] or the importation of convict made goods
into any State where their receipt, possession or sale is a violation of
local law.[199] It may require employers to bargain collectively with
representatives of their employees chosen in a manner prescribed by
statute, to reinstate employees discharged in violation of law,[200] and
to permit use of a company owned hall for union meetings.[201] It may
enforce continuance of the relationship of employer and employee in the
event of a strike as a consequence of, or in connection with, a current
labor dispute.[202] The fact that property subject to rent control in
time of war suffers a decrease in value does not make such restriction
offensive to the due process clause.[203]

The Postal Service

In its complete control over the postal service Congress may exclude
lottery advertisements or any other matter objectionable on grounds of
public policy.[204] An order requiring return to the senders of all
letters addressed to a concern engaged in a fraudulent enterprise, or to
its officers as such was held reasonable and valid because an order
limited to matter obviously connected with the