The United States allows inhabitants of 37 countries to enter the United States without a visa, as long as they extend the same privilege to U.S. citizens. Sen. Barbara Boxer is proposing to add Israel to that list - but without requiring equal treatment for Americans traveling to Israel.

Instead, the legislation the California Democrat has introduced would exempt Israeli visitors from visa requirements as long as the U.S. government certifies that Israel "has made every reasonable effort, without jeopardizing the security of the state of Israel," to admit Americans without a visa.

What that means, according to critics of the Israeli government, is that Israel can continue to exclude Americans who are either Arab or Muslim, or who belong to groups that oppose Israeli policies. Requiring a visa for visitors allows the government to bar them from entering, or to limit their activities or the length of their stay.

The legislation "would codify into American law discrimination against American citizens," said Sydney Levy of Jewish Voice for Peace, a group that opposes Israeli occupation of the West Bank and Gaza.

Seal of approval

The Council on American-Islamic Relations, a Muslim advocacy group, said the bill would give a U.S. seal of approval to "Israel's well-documented ethnic and religious profiling."

As the organization noted, the U.S. State Department has officially advised travelers that U.S. citizens "of Arab or Muslim origin have experienced significant difficulties in entering or exiting Israel or the West Bank."

The advisory on the department's website also notes that Americans seeking to enter Israel, the West Bank or Gaza "have been subjected to prolonged questioning and have been denied access to consular officers, lawyers and family members."

Boxer, in a statement to The Chronicle last week, said the criticism of Israel's practices and of her legislation is unfounded.

"Every country in the world retains the right to deny entry to individuals based on national security concerns - including the United States," she said.

The senator said her bill would not endorse any discriminatory policies, but instead "would give the United States leverage to ensure that Israel welcomes Americans into their country."

The bill, S.462, was introduced in March by Boxer and Sen. Roy Blunt, R-Mo., and has 25 other co-sponsors and the support of the powerful American Israel Public Affairs Committee. Titled the U.S.-Israel Strategic Partnership Act, it includes a proposed increase in the U.S. weapons stockpile in Israel and an exemption for Israel from some export licensing requirements.

The 38th nation

The visa waiver provision would add Israel to the 37 nations - most of Europe, along with Japan, South Korea, Australia, New Zealand and several other Asian countries - whose citizens can enter the United States with only a passport and stay for up to 90 days. Similar legislation was introduced in the House last year by Rep. Brad Sherman, D-Sherman Oaks (Los Angeles County).

The main purpose, Boxer's office said, is "increasing visits between our two countries, boosting tourism and strengthening the economies of both countries."

But Jewish Voice for Peace cites the case of a woman who said she learned from personal experience that not all tourists are welcome in Israel.

Sandra Tamari, a U.S.-born citizen of Palestinian descent, a Quaker and a member of the Palestine Solidarity Committee in St. Louis, said she went with an interfaith group of about 30 people to visit the West Bank last May.

She said Israeli authorities pulled her aside at the airport in Tel Aviv, asked her about her family and her background, then jailed her overnight and put her on a plane back to the United States.

While in custody, she said, she telephoned the U.S. Embassy. Tamari said the person who took her call asked her immediately if she was Jewish, and, when told she wasn't, replied, "Then there's nothing I can do to help you."

A misunderstanding?

Tamari said the State Department later told her she must have misunderstood the embassy official.

Department spokesman Mark Toner, asked about the incident at a June 2012 press briefing, said, "We would never deny assistance to any American citizen, regardless of their religious or ethnic background."

Regardless of current U.S. policies, Tamari said in an interview last week, Boxer's bill would change U.S. law and "create a second-class citizenship category for Arab Americans, for Palestinian Americans, for Muslim Americans."

Bob Egelko is a San Francisco Chronicle staff writer. E-mail: begelko@sfchronicle.com