"On the ground, tank destroying missile systems would by their very nature be quite usable in an offensive, mobile fashion to neutralize any disadvantage in armor," Giraldi said.
Giraldi observed that the tactical impact of such an arms package had been seriously discussed in US military and government s circles.
"There is also considerable debate over what constitutes a lethal but defensive weapon, hence the discussion of tank vs anti-tank," he said. "To keep the weapons from falling into the wrong hands there will be provisions in the arms sale agreement that will establish a monitoring system to confirm that the arms are still in the hands of the authorized users."
However, there was good cause to doubt whether such safeguard would actually work in practice, Giraldi acknowledged.
"In the past, however, those provisions have proven nearly impossible to enforce and the situation in Ukraine with militias on the ground does not suggest that one should be optimistic," he cautioned.
Giraldi warned that the weapons sales would certainly be viewed unfavorably by the Russian government.
Technically approving such an arms package for Kiev would not break the Minsk Accords although it would certainly escalate tensions, Giraldi said.
"Minsk does not define what is meant by the defensive weapon as far as I know so one could plausibly argue that the sale of anti-tank and other battlefield refinements would not necessarily be a violation," he said.
Many of these dangers associated with sending lethal arms to Ukraine have already been pointed out by US officials in internal government policy discussions, Giraldi said.
"The US government has taken so long to review the arms sale to Ukraine because there is some, though admittedly not much, opposition to it at the State Department and elsewhere due to concerns that it will cause the existing crisis to escalate," he said.
In September 2016, the US House of Representatives approved legislation to allow the supply of lethal "defensive" weapons to Ukraine, but the law still needs to be approved by the US Senate and signed by the US president.
The Ukrainian government has been conducting a military operation in the country's eastern regions since April 2014, after local residents refused to recognize the new government in Kiev. In February 2015, Kiev and the Donbass militias signed a ceasefire deal. Despite the agreement, both sides have been reporting violations of the ceasefire
Philip Giraldi is executive director of the Council for the National Interest, a group that advocates more even-handed US government policies in the Middle East.
