By Tom Hennigan | Correspondent of The Christian Science Monitor

             BUENOS AIRES, ARGENTINA - January afternoons in Buenos Aires are usually best endured in the shade. But despite being one of the
             hottest days yet this summer, Monday afternoon saw 20,000 people take to the streets in protest against the government of left-wing
             Peronist Nestor Kirchner.

             The march was organized by groups from Argentina's piquetero, or picketer, movement to demand the release of fellow activists and the
             repeal of a pro-business labor law. At the forefront of the antiglobalization movement, piqueteros are unemployed people who demand jobs,
             social assistance, and an end to neoliberal economic policies.

             Formed almost a decade ago, the piqueteros are increasingly taking to the streets to protest pro-market policies. In recent years, the
             piqueteros and similar movements elsewhere in South America have played a part in bringing down governments in Argentina, Bolivia, and
             Ecuador.

             President Kirchner is only one of several recently elected left-wing presidents in the region who is facing political attack from those further
             left on the political spectrum. To varying degrees, his colleagues in Brazil, Ecuador, and Bolivia face similar challenges, drawing fire for their
             cautious economic approach, which protesters ascribe to their having "sold out" to the International Monetary Fund (IMF).

             "Kirchner is a president who represents the interests of the IMF and global capital in general, not the people of Argentina," says Carlos
             Macagno, a piquetero demonstrating on Monday.

             With Argentina's right-wing parties in disarray and much of the left allied with the president, the piqueteros are the most visible opposition
             Argentina's government now faces. Because nearly 1 in 5 Argentines is unemployed, there are plenty of piqueteros - an estimated
             half-million. They are well organized, and can attract thousands of followers. While the majority are friendly to the government, more than
             100,000 of the most militant are not.

             The two sides have plenty of beliefs in common. Both blame neoliberalism for Argentina's economic mess, and both insist that the
             country's enormous external debt should not be paid at the expense of the country's poor.

             But the piqueteros say that by striking a recent deal with the IMF, Kirchner failed his first major test of that common ideology. "In the deal
             with the IMF, Argentina agrees to run a primary budget surplus of 3 percent of GDP," says piquetero Eduardo Tiglio. "That is a lot of money
             for a country like Argentina - that is needed for food, clinics, and education. Instead, it will go abroad to service the debt."

             When Argentina signed its deal with the IMF in September, Kirchner was widely perceived to have won generous terms from the Fund. But
             the piqueteros contended that any deal at all was proof that the president's pledge to put Argentina's interests before those of the
             international financial community would not to be backed up with deeds.

             "This president says one thing and does another," says piquetero Eduardo Alanis, who attended Monday's march.

             Next door in Brazil, the landless peasant movements, allies of the piqueteros, are demanding that left-wing President Luiz Ignacio "Lula" da
             Silva fulfill his campaign pledge to intensify land reform. The number of farms seized by groups of landless peasants doubled in 2003, his
             first year in office.

             Lula's moderate course, which has also included an agreement with the IMF, has drawn fire from unions and members of his own party,
             several of whom were expelled from the party last month. Brazil now says it won't renew its accord with the IMF when it expires later this
             year.

             In Ecuador, President Lucio Gutierrez is involved in a power struggle with his former supporters after he abandoned his populist election
             program and adopted the IMF's economic prescriptions. "He has bowed to pressure from the IMF to abandon his policies," says Jose
             Yongan, a spokesman for CONAIE, an indigenous organization in Ecuador, that has vowed to oust Gutierrez.

             For presidents Kirchner and da Silva, the hope is that projected economic growth in 2004 will finally start to create jobs and fund
             public-works projects - and thus soften the sting from the protests. Still, the situation remains volatile. A small bomb injured 26 people at a
             piquetero demonstration in Buenos Aires last month. The piqueteros say the bomb was placed by elements in the country's security
             forces, emboldened by a recent hardening in the government's stance toward the protestors.

             Analysts warn that confronting piqueteros head on will only help their cause. Says Sergio Berensztein, professor of political science at Di
             Tella University in Buenos Aires, "These are people that need repression to validate their stance."