Gwyneth Paltrow & Blythe Danner

Gwyneth Paltrow didn't invent the ritual of issue-oriented visits by celebrities to Capitol Hill; but on her recent visit she added her personal touch — she brought her mother. Other celebrities might have been happy with a mother-daughter shop- ‘til-they-drop morning in Beverly Hills. But Paltrow, movie star ("Iron Man," and our favorite "Shakespeare in Love"), owner of the lifestyle website Goop, cookbook writer and fashion trendsetter, accompanied by stage and screen star Blythe Danner, came to Washington to lobby the U.S. Senate.

They were campaigning against legislation passed by the House essentially blocking attempts by individual states to put labels on genetically modifi ed (GMO) food. The two actors are backing the so-called "Just Label It" campaign which is now focusing on trying to persuade senators not to follow the House's lead and pass the law. Paltrow also delivered a petition with more than 200,000 signatures urging President Obama to veto the law — called the Safe and Accurate Food Labeling Act of 2015 — should it land on his desk.

Modern biotechnology, or gene technology, can modify the genetic make-up of living cells and organisms to give them a new property. For instance, it can improve a food's quality or nutritional value or change its resistance to a specifi c disease or drought. The U.S. is at the forefront of GMO technology, which many other developed countries have been wary about accepting. The European Union has recently relaxed its earlier ban on GMO-altered food. It now gives its 28 member states the option to allow importation, mainly from the U.S., from a list of EU-permitted GMOs.

"I'm not here as an expert," said the 42-year-old actress and mother of two. "I'm here as a mom, as an American mom who thinks I have a right to know what's in the food I'm serving my family." Both sides of the current fi ght over food labeling come to opposite conclusions based on more or less the same arguments. Paltrow said scientifi c information on GMOs was still insuffi cient, and consumers needed to be allowed to make a choice.

Those who defend GMOs say there is not enough scientifi c evidence that genetic modifi cation actually justifi es a warning to consumers. "The science is still inconclusive about GMOs and there are arguments that they could possibly be harmful and there are arguments that they could possibly be incredibly benefi cial and drought resistant and have extra nutrition. At this point we just don't know," Paltrow told reporters. "Much the way I want to know if my food is farm-raised or wild or if my orange juice is fresh or from concentrate, I believe I also have the right, and we all have the right as Americans, to know what's in our food."

Blythe Danner, 72, added, "The herbicides alone that they have to treat these GMOs with are off the charts."

Standing with them at the Capitol were Sens. Barbara Boxer (D-CA), Jon Tester (D-MT), Patrick Leahy (D-VT) and Richard Blumenthal (D-CT). High-profi le visits to Congress such as this one by celebrity activists in support of their favorite causes focus media attention on the issue, but the long-term impact of these periodic apparitions on altering views — and votes — has always been the subject of debate.

In the past year or so, lawmakers appear to have become more selective about celebrity photo ops, and in particular celebrity testimony before committees. In 2014, for example, the House Foreign Affairs Committee decided not to include Ben Affl eck in its hearings on the eastern Congo because it did not regard him as an expert witness. The Senate Committee, however, did hear Affl eck, who has made several trips to the Congo, founded an advocacy group to help the area and was arguably well versed in the situation on the ground.

Neither Paltrow nor her mother professed to have any special knowledge of GMOs, but the public relations impact was hard to beat. Both women brought a rare touch of elegance to the occasion. Paltrow wore what every female senator doesn't wear on the Hill — navy palazzo pants and a white, billowy feminine version of a button-down shirt while Danner was in a crisp white pantsuit and straw hat.

The opposition was clearly taking no chances. On the fringes of the event, a representative of the opposition handed out a news release saying Paltrow "Ignores Concerns of American Families in Lobbying Against Bipartisan Legislation." One food industry lobby group, the Coalition for Safe and Affordable Food, that has argued somewhat disingenuously that GMO labeling would create "consumer confusion" and increase grocery bills, dismissed Paltrow as one of those "out of touch Hollywood celebrities" who want to "enshrine their lifestyle choices" on everyday American families.

If you're attacked you must be doing something right, argued Sen. Boxer, coming to Paltrow's rescue. "When people ridicule you, whether you're a senator or a teacher or a truck driver or an actress, they want to shut you down," she said. "If you weren't effective, they wouldn't bother."