A senior Chinese envoy's visit to Taiwan for trade talks has sparked a backlash among critics who fear the Taiwanese government's China-friendly policies are opening the door to eventual unification with the mainland. Chen Yun-lin flew Monday from Beijing to the central Taiwanese city of Taichung a day after tens of thousands of pro-independence demonstrators marched through its streets to protest President Ma Ying-jeou's push to link the island's economy ever closer to China's. On Monday, police stopped several hundred protesters from besieging Chen's hotel. Many of the protesters view Chen as the spearhead for communist Beijing's proclaimed policy of uniting Taiwan with the mainland - the core of its Taiwan approach since the sides split amid civil war in 1949. They see Ma's policies as endangering Taiwan's sovereignty and its hard-won democracy. Despite the protests, Ma's push for a partial free trade agreement with Beijing is still on track. His Nationalist Party enjoys a substantial majority in the legislature, allowing him to implement virtually any deal he wants. On Tuesday, Chen and his Taiwanese hosts are expected to sign three minor economic accords, and discuss the free-trade deal. Ma says it will be signed in the spring of 2010. Since taking office in May 2008, Harvard-educated Ma has eased tensions across the 100-mile (160-kilometer) -wide Taiwan Strait to their lowest level in 60 years, turning his back on predecessor Chen Shui-Bian's pro-independence policies. He has pushed a welter of business-boosting initiatives, including regular air and sea links with the mainland and ending across-the-board restrictions on Chinese investment in Taiwan. Shortly after his arrival in Taichung, Chen Yun-lin acknowledged the progress the sides had already made and said he hopes that further gains can be made. "History has proved and will prove that the two sides of the Strait are marching ahead on the right path," he said. "We want to move down the road of peace." Many in the main opposition Democratic Progressive Party believe Ma's China-friendly push is setting the stage for an eventual Chinese takeover of the island, which the president vehemently denies. The DPP says Ma's intended trade deal - formally known as the Economic Cooperation Framework Agreement, - will flood the island with cheap Chinese products, prompting massive job losses. "Our president has turned blind to the possibility that jobs will be lost" after signing the agreement, DPP Chairwoman Tsai Ing-wen told protesters Sunday. Ma rejects that assertion, saying the trade deal is necessary to prevent Taiwan's economic marginalization amid growing commercial ties between Beijing and neighboring Asian countries. Washington strongly supports Ma's approach. Despite shifting its China recognition from Taipei to Beijing in 1979, it remains Taiwan's most important foreign partner and fears being drawn into the armed conflict that Beijing threatens would follow any opposition move to formalize Taiwan's de facto independence. It sees Ma's policies as strongly reducing that possibility. Ma has said repeatedly that unification is not on the cards during his presidency - if he's re-elected, his term would last until 2016 - and most Taiwanese take him at his word. But some in his party favor union with the mainland, so many in the opposition fear that steps toward that end could still be taken while he is in office. Most Taiwanese support Ma's argument that closer economic ties with China would aid Taiwanese prosperity, but a dip in his popularity in recent months because of missteps on other issues has hurt public backing for his pro-China policy. Ma's standing was hurt by his mishandling of the response to a devastating typhoon that hit Taiwan in August, then more recently over secret negotiations on the removal of a ban on some US beef imports. Earlier this month Ma's Nationalists defeated the DPP by only two percentage points in local elections - a far cry from the 17-point margin that Ma enjoyed over his DPP rival in the March 2008 presidential poll. A further round of local elections is scheduled for late next year. Should the Nationalists fare poorly in those elections as well, Ma could face problems in Taiwan's 2012 presidential poll.