The U.S. Congressional Research Service(CRS) said that South Korea and the United States have demonstrated inconsistent policy cooperation on various issues, taking the deadlocked defense cost-sharing talks as an example. 

In its recent report on the latest developments in relations of the two allies, the CRS said that although South Korea is one of the most important strategic and economic partners of the U.S., policy cooperation between the two nations has been inconsistent under the administrations of Donald Trump and Moon Jae-in. 

The CRS report updated last Wednesday said that the two countries have generally resolved differences on trade and North Korea policy, but tensions remain in other areas.

The report, in particular, cited the deadlocked negotiations on how to share defense costs for the upkeep of U.S. Forces Korea.

It said that President Trump's calls for a steep increase in Seoul's contributions, paired with his criticism of the value of other U.S. alliances, has raised concerns in Seoul about U.S. security commitments.