Next to asking voters to stay the course, President Reagan's other slogany appeal for support for Republican candidates in the past few months has been that his critics were mere negativists. What are their alternatives? he asked. They have none, he answered. They lack fresh ideas.

This is as wide of the facts as any of the other Reagan misstatements and deceits that have marked his presidency. If anything, the past few months have seen a wide spray of ideas gushing out of alternative spigots.

To take only three of the best: "The Once and Future Democrats: Strategies for Change" By Rep. Paul Simon (D-Ill.); "A Path for America: Proposals From the Democratic Left" by Michael Harrington in the current issue of Dissent magazine, and the recent hearings of Rep. Ronald V. Dellums (D-Calif.) on an alternative military budget.

Harrington leads the socialist wing of the Democratic left. Dellums is as far left as anyone in Congress can be and still get elected. And Paul Simon's liberalism has developed after four terms of representing the poorest of Illinois' 24 congressional districts.

The three are liberals of differing nuances, but none has used the resurgence of the Republican party as an excuse to back off and repackage themselves as neolib tinkerers. Nor can any of the three be dismissed as mere grandstanding Lefties whose reformist ideas are fine except they aren't "realistic."

Harrington's grasp on reality is firm when he states that the country is in a "profound crisis, and not just because the affably mean, pragmatic ideologue who is President of the United States is destroying some of the most important gains ever made by the people of the United States."

Among other specifics, Harrington discusses the railroads. They are now in severe decline, from unsafe roadbeds to poor performance. While French and Japanese trains get faster, ours get slower. Harrington refers to a Congressional Joint Economic report stating that "the average speed of passenger trains in the United States has declined from 70 mph in the mid-1950s to a current average of 40 mph." Jobs would be created and the public good served, Harrington argues, if "a number of democratically structured regional rail corporations" were created to revive the railroads.

Dellums' alternative military budget was debated on the House floor as a detailed proposal for military sufficiency. Unlike other critics of the military budget, who rightfully attack weapons that cost too much and don't work, Dellums points out that the major weapons systems account for only 12 percent of the 1983 authorization. The bigger savings would come out of the more than 50 percent piece of the pie: operation, maintenance and personnel. He calls for a 5 percent reduction in troop levels, the rejection of expanding the Navy fleet to 620 ships and an effort to get our allies to spend more of their own money on their defense.

Simon criticizes Democrats for the usual political sins of "preelection concern and postelection indifference." But he believes his party "has slipped in part because of its success. The programs have succeeded well enough so that people who have been helped by government have increased their income, moved to the suburbs (mentally, if not physically) and now vote Republican with their neighbors. Not only does voting Republican become socially more acceptable, but as a person's income goes up it becomes easier to find flaws in the expenditures of public funds and reasons why those funds should stay in 'my' pocket rather than go to the federal government for distribution to others."

If the progressive wing of the party has been successful, Simon argues, it shouldn't suddenly strain to come up with new ideas merely for the sake of newness. Considering the attention neoliberals have created for themselves -- the Democrats' newness lobby -- Simon's idea of let's stay with what has worked has a freshness of its own.

Reagan couldn't have been expected to acknowledge that alternatives to his own ideas are being expressed. His retort of "shut up" to a right-wing fanatic expresses his sentiment to everyone who disagrees with him, except that the views of people like Harrington, Dellums and Simon are well short of the fanatical. If anything, they represent mainstream liberalism. Reagan can't shut up that, so he shuts it out.