The Senate is totally dysfunctional because of the "two-track system" that was introduced in 1970. 

Before that, any senator could bring the work of the Senate on a bill to a temporary halt by filibustering – i.e., by talking and talking interminably (perhaps including reading the phone book aloud) until the bill was withdrawn or a sufficient supermajority of senators voted cloture (i.e., to cut off debate and proceed to a vote on the bill).  After cloture, passing the bill would require a majority (51 senators) to vote in favor.  The new rule allowed the majority leader of the Senate to set aside a bill when a filibuster was threatened so that the Senate could move on to other business.

The filibuster is an important protection against hasty action by the Senate and against disregard of the concerns of the minority party.  The two-track rule was intended to weaken these safeguards by reducing the ability of senators to bring Senate business to a halt, but it has had exactly the opposite effect, perversely impeding the passage of all bills.

In practice, the new rule has meant that any senator can prevent consideration of any bill by simply announcing the possibility of a filibuster.  The bill is set aside, never to be seen again unless or until the threat of a filibuster is withdrawn.  This introduced the "virtual filibuster": opponents of a bill no longer need to deliver an actual filibuster, but just say they might.

Because of this rule, very few bills can now pass unless a supermajority (currently 60 senators) are willing to vote cloture.  In other words, Senate bills now require 60 votes to pass, not just the simple majority intended by Article 1, Section 7 of the Constitution.

The Republicans now have only 51 seats, so it may seem that there is no way they can "repeal and replace" Obamacare, or pass tax reform, or anything else, without Democrat votes.  There is virtually no chance the Democrats will cooperate, since their best chance of regaining control in 2018 is to let the Republicans come across, as they do so often, as incompetent, ineffectual buffoons. 

Bills that deal only with urgent fiscal matters are exempt from filibusters and can thus pass with 51 votes.  This process is called reconciliation.  Mitch McConnell is trying to use this provision, known as the Byrd Rule, to pass some bits of a health care bill, but he cannot include the most important reforms.  The predictable result is a train wreck that makes Obamacare worse, not better, and satisfies nobody from Bernie Sanders to Rand Paul.  This pathetic effort cannot and will not work, and we will soon see a similar debacle over tax reform.

The sad thing about this is that it is totally unnecessary.  Mitch McConnell has at least two weapons he could use and would be using already if only he had the gumption.

First, the two-track system allows but doesn't require him to put aside a bill whenever a filibuster is threatened.  If Sen. Footdragger (D) announces a virtual filibuster, McConnell can say that in order to accommodate him, the Senate will stay in session, but there will be no business scheduled until the senator withdraws or his fellow senators vote cloture.  If necessary, the whole Senate can just sit there, doing nothing,

If the senator starts a real filibuster, the Democrats will soon take the blame for delaying critically needed legislation.  If he does not keep talking, any Republican can raise a point of order: since no filibuster is in progress, the Senate should vote on the bill.  This will be referred to the chair for a ruling.  The chair will probably agree, but it will really matter, since a ruling by the chair can be reversed by a simple majority vote.  In other words, the Republicans could force passage of the bill.

This point-of-order procedure also allows the majority party to change any rule of the Senate if it wants to enough.  In theory, changing a rule requires a two-thirds supermajority, but all it really takes is an objection when the rule is applied.  The point of order doesn't have to be correct or even make any sense. 

For example, when Senator Footdragger announces his virtual filibuster, any Republican can raise a point of order, claiming that the two-track rule says that (a) any proposed filibuster must start within five calendar days of its announcement; (b) the majority leader must make room for it on the Senate calendar; and (c) that pausing a filibuster for more than 30 minutes (except for bathroom breaks, etc.) constitutes withdrawal, allowing an immediate vote on passage of the bill in question.  This is not at all what the rule says, so the chair will deny it.  Then the majority leader will call for a vote overturning the chair's ruling.  If 51 senators vote in favor, the two-track rule will be changed to the new version.

This may seem insane, and it is indeed barely credible that the future of our country could depend on such shenanigans – but this is what is called the "nuclear option," and it is precisely the technique Harry Reid used in 2013.  The Senate rules required 60 votes to confirm appointment of judges, but Reid raised a point of order, saying falsely that only 51 votes were needed (except for the Supreme Court).  The chair denied his claim, and the Democrat majority then overruled the chair – so now ideological judges are easier to appoint.  Mitch McConnell himself used the same technique last April to appoint Neil Gorsuch to the SCOTUS.

The principal objection to these bizarre tactics is that the perpetrators may be sorry when control of the Senate shifts to the opposite party.  Because of Reid's action, the Republicans may be able to stack federal courts at all levels, up to and including the SCOTUS, before the Democrats regain power.

This objection does not seem to apply to using the nuclear option to change the two-track rule so that a filibuster requires actual talking.  It would not prevent the minority party from requiring a 60-vote cloture resolution before passing a bill, but making it stick would demand real determination, effort, and stamina.  That seems to be in the interests of both parties, regardless of which one is in power.

So please, Mitch, just do it.  Use the nuclear option to restore the filibuster to its proper role, and then start fulfilling your responsibility to all the voters who gave you the majority by passing real bills that can make America great again.  If the Democrats object, make them mount real filibusters until they get the message that intransigence and obstructionism will not earn them votes next year.

If you don't do this, Mitch, nothing will get done, you will be blamed, and both Houses will revert to the Democrats next year.  You will be hanged in effigy in every Republican district in the country if you let this happen.