President Barack Obama wants all 50 states to provide pre-kindergarten schools for 4-year-olds, a plan that the White House says will result in better prepared students and ultimately a more educated workforce.

Obama's plan, unveiled in his State of the Union address Tuesday, would provide federal government support to the states to provide access to preschool for all low- and moderate-income 4-year-olds.

Obama also wants the federal government to give the states incentives to provide full-day kindergarten.

Obama campaigned in 2008 on a plan for universal pre-school. Advocates say such a plan results in improved student test scores and reduced spending on government assistance programs. Skeptics say that evidence of positive results is limited and that preschool can encourage children to spend less time with their parents.