PHILADELPHIA (May 24, 2012)—Republican presidential candidate Mitt Romney is facing some tough questions about how his education proposals would affect black communities.

On Thursday Romney visited a West Philadelphia charter school, a day after he declared that education is the "civil rights issue of our era."

Romney repeated that declaration during the school visit, but struggled to defend his view that class sizes aren't a major factor in educational success.

Local African-American leaders also said his push for more two-parent families isn't realistic in their community.

The charter school's founder also said he's not sure whether Romney understands the needs of the African-American community.

A recent poll found that 90 percent of blacks would vote for President Barack Obama, the first black U.S. president.