% replaces any number of letters (la% - lake, lamp)_ replaces one letter (ca_ - car, cat)

Crossword clues for The U.S. and Can. are in it 3 letters

AnswerClue
NSAU.S. org. hidden in two U.S. state names
ATLU.S.-U.K. separator
TUEWhen to 7-Down in the U.S.
CIAMI6 : U.K. :: __ : U.S.
FEDU.S. enforcer
WIE2014 U.S. Women's Open champ
NIHU.S. medical research agcy.
AAFU.S. air arm, once
ELSTwo-time U.S. Open winner
FTCU.S. commerce watchdog
NSAU.S. eavesdropping org.
OSULargest U.S. campus, enrollment-wise
ELS1994 U.S. Open champ
SAN__ Ysidro, busy U.S./Mexico border site
RTEU.S. 1, for one
NSAPart of the U.S. intelligence community
FBIU.S. crime solvers
NSAU.S. cryptanalysis org.
DOLU.S. currency
TEMEnd of the title of the third-in-line successor to the U.S. presidency
LETU.S. Open call
NALDefunct U.S. airline
NIHU.S. biomedical research agcy.
VOAU.S. govt. broadcaster
PSTOnly two U.S. states, Wash. and Cal., are entirely within this zone
NEA3.2 million-member U.S. union
CTY30 U.S. states have one named Washington
INSU.S. border protectors
ELS1997 U.S. Open champ
DELSecond-smallest U.S. state
ATLU.S. seaboard
AFLU.S. trade alliance founded in 1886
DEMDesignation for many a U.S. 55-Down
PROU.S. Open entrant
TVAEnergy org. whose board members are confirmed by the U.S. Senate
AAUOrg. that once ran U.S. track and field
KGBRobert Hanssen betrayed the U.S. to it
MENMost U.S. senators, Best Director Oscar nominees, and crossword editors, lamentably
GENU.S. Grant or R.E. Lee
TWAU.S. airline
SSAU.S. provider of benefits
SEEU.S. National Anthem's fifth word
GNPU.S. economic fig.
SOOU.S. -Can. canals
GODWord on all U.S. coins
SETU.S. Open division
ALTAbbr, on some U.S. Route bypass signs
TWAErstwhile U.S. carrier
AGRU.S. dept. concerned with meat inspection
CIAU.S. equivalent of Britain's MI6