WASHINGTON — The U.S. territorial missile shield would have a 92 percent chance of intercepting an ICBM launched from Iran, and plans formulated under former President George W. Bush to put interceptors in Europe would have increased the shield’s effectiveness by only three to four percentage points, Marine Corps Gen. James Cartwright, vice chairman of the Joint Chiefs, told the Senate Armed Services Committee during a Sept. 25 hearing. Cartwright was responding to claims that the United States was abandoning protection of its homeland by moving away from the previous administration’s plan to place 10 interceptors in Poland and a radar in the Czech Republic.

The new plan, announced Sept. 17 by the Pentagon, will use a ship-based missile defense system incapable of intercepting long-range missiles headed for the United States until a bigger interceptor is ready around 2020.

Cartwright said the new U.S. plan for defending deployed forces and European allies is not a step back from commitments made to Poland and the Czech Republic. He said the plan was formulated in response to the Pentagon’s assessment that massive raids of short- and intermediate-range missiles from Iran constitute the most probable and immediate threat.

Some members of the Senate Armed Services Committee blasted the decision as concession to Russia and a slap in the face to the United States’ NATO allies.

“The decision by the administration to back away from its missile defense commitments to the Czech Republic and Poland can only demonstrate to the rest of Europe that the United States is not prepared to stand behind its friends,” said Sen. John McCain (R-Ariz.), the committee’s ranking member.