President Donald Trump has made an enormous bet that takes the entire Republican agenda hostage and could even shorten his time in office.

His bet is that now, with James Comey under fire across the political spectrum, he could fire the FBI director investigating his campaign and associates with a minimum of blowback.

The muted initial reaction from many Republicans offered encouragement to the White House. But subsequent criticism, as the news sank in, from the Republican senator leading the Senate Intelligence Committee investigation and others underscored the risks facing Trump.

Foremost among them, in the short term, is that Trump's decision represents a tipping point for Republican lawmakers who have looked past the president's behavior to pursue goals on issues such as health care, tax cuts and deregulation of American business.

Heat from their constituents, visible so far in Trump's weak poll ratings and in raucous town hall gatherings, can paralyze congressional majorities — especially those as thin as the GOP's 52-48 edge in the Senate.

The more easily controllable House barely passed the American Health Care Act last week. The troubled effort to repeal and replace Obamacare has put off the effort to pass tax cuts, placing both priorities in jeopardy.

For Trump, the long-term threat is greater. His abrupt move, by prompting questions about the "rule of law" in the words of Democratic Senate Intelligence Committee co-chair Mark Warner, will stoke unease or even outright opposition to the president in major American institutions, the career government services and on the campaign trail as members of Congress prepare for the 2018 mid-term elections.

In special election contests already, Democrats have commanded unusual energy and vote totals in Republican-leaning districts. The June 20 runoff for a Georgia House seat Republicans have held for decades will provide an early indication of Democrats' ability to compete next year for control of the speaker's gavel, which appeared highly unlikely just a few months ago.

Mid-term election handicappers note the potential for a political "wave" mirroring the 2006 Democratic sweep and 2010 Republican landslide. Another one in 2018 could bring Nancy Pelosi back as House speaker.

If that happens, recent history gives Trump and the GOP reasons for grave concern. In what came to be known as the "Saturday Night Massacre," President Richard Nixon fired Watergate special prosecutor Archibald Cox in October 1973.

The process of impeachment began in the Democratic-controlled House less than four months later. When Nixon's Republican support in the Senate collapsed six months later, he became the only president to resign his office. So far.